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Walk behind unit electrical problem
#1
Richie F
Richie F
I'm working on a model SW36A14FS
s/n J6100114
The owner of this machine has disconnected/by passed all safety switches.
With the engine running when the PTO is engaged the engine shuts off.
Unplugging the ground wire for the Magneto the PTO will function properly.
I realize something is still in the circuit to ground out the Magneto when using the PTO switch.
Both harnesses are in good shape. No chafing anywhere.
I tested the resistance of the PTO coil and have 3.3 ohms.
Also tested the diode and it's good.
I do have the wiring diagram for this machine.
Thanks
s/n J6100114
The owner of this machine has disconnected/by passed all safety switches.
With the engine running when the PTO is engaged the engine shuts off.
Unplugging the ground wire for the Magneto the PTO will function properly.
I realize something is still in the circuit to ground out the Magneto when using the PTO switch.
Both harnesses are in good shape. No chafing anywhere.
I tested the resistance of the PTO coil and have 3.3 ohms.
Also tested the diode and it's good.
I do have the wiring diagram for this machine.
Thanks
#2
tom3
tom3
Some of these safetys are not just make or break contacts. Maybe a third wire deal to prove the circuit is intact. Maybe a set of switches in series. Have to dive into the schematic and see where the problem is I suspect.
#3
Richie F
Thanks for your interest in this problem.
Richie F
Some of these safetys are not just make or break contacts. Maybe a third wire deal to prove the circuit is intact. Maybe a set of switches in series. Have to dive into the schematic and see where the problem is I suspect.
Thanks for your interest in this problem.
#4
B
bertsmobile1
B
bertsmobile1
I am guessing that it has a manual clutch.
If not then there will be safety switch built into the PTO switch.
Hope you are charging MR D Head by the hour to sort out his mess.
If not then there will be safety switch built into the PTO switch.
Hope you are charging MR D Head by the hour to sort out his mess.
#5
Richie F
First off Mr D Head is a personal friend of mine. ( I know what you're implying) and no money is involved in this repair.
Second if you would look at the wiring diagram the clutch is power by electric.
Thanks
Richie F
I am guessing that it has a manual clutch.
If not then there will be safety switch built into the PTO switch.
Hope you are charging MR D Head by the hour to sort out his mess.
First off Mr D Head is a personal friend of mine. ( I know what you're implying) and no money is involved in this repair.
Second if you would look at the wiring diagram the clutch is power by electric.
Thanks
#6
G
geelee
G
geelee
a wiring diagram is can be found on partstree under the model and serial number for that machine
#7
tom3
tom3
Simple solution would be to put a momentary contact switch on the mag. kill line to ground. No big voltage or current in this circuit. Bypass all the stuff. Nice big red button on the dash. Probably not legal in all 50 states though.
#8
NorthBama
NorthBama
I would use an OHM meter and find what is connecting the kill wire to ground to kill the engine when pto switch is pulled to engage the clutch.
#9
B
bertsmobile1
B
bertsmobile1
In which case my first reply is still valid, the PTO switch will have several safety circuits running through it and they are very difficult for people with no idea about what they are doing or basic DC electronics to bypass properly.
As you might have already guessed I do not have much time for people disabling safety switches, regardless of the fact I do not believe in them. The best safety switch is between your ears.
Apart from seats on ZTR's which were too sensitative there is however little reason to dissable switches unless the person has a serious dissability , as none of them prevent quick & efficient use of the mower.
We have had this discussion on here 100 times before and just like gun regulations it is very polar with both sides fairly well entrenched in their ideas.
To be frank, I would rather see mowers made safe to use with guards and not any of the switches bar the seat switch or some other dead man device that kills the machine stone dead the instant there is no one in the seat or the operator has a seizure / heart attack etc.
If we came across people on a daily basis missing fingers , hands , toes etc from careless use of their mowers then it would be reinforced in our minds that these things are very very dangerous tools.
But unfortunately all of the safety gear installed makes it next to impossible to injure yourself so people use their mowers in a totally brain dead fashion, in a dangerous manner in dangerous situations then sue the factory when they succeed in doing damage.
And I am not trying to be preachy here .
I have a customer with Lupis so she can hot hold a bail for any length of time.
The solution is a pin that holds the bail closed tied to a string around her wrist so if she falls over the mower stops , not bypassing the bail all together.
So if you have the wiring diagram just follow the kill wire back from the coil to where ever it grounds, and there will be a lot of places where this can happen.
If necessary print it out a couple of times, pinch a coloured pencil from one of the kids and trace over the kill wires for each situation or use different coloured wires for PTO on & PTO off
IF there is no pin out for the PTO switch then pull it out and measure across the contacts.
It is a simple sliding contact switch that connects left to right and generally all of the middle row will be tied together.
As you might have already guessed I do not have much time for people disabling safety switches, regardless of the fact I do not believe in them. The best safety switch is between your ears.
Apart from seats on ZTR's which were too sensitative there is however little reason to dissable switches unless the person has a serious dissability , as none of them prevent quick & efficient use of the mower.
We have had this discussion on here 100 times before and just like gun regulations it is very polar with both sides fairly well entrenched in their ideas.
To be frank, I would rather see mowers made safe to use with guards and not any of the switches bar the seat switch or some other dead man device that kills the machine stone dead the instant there is no one in the seat or the operator has a seizure / heart attack etc.
If we came across people on a daily basis missing fingers , hands , toes etc from careless use of their mowers then it would be reinforced in our minds that these things are very very dangerous tools.
But unfortunately all of the safety gear installed makes it next to impossible to injure yourself so people use their mowers in a totally brain dead fashion, in a dangerous manner in dangerous situations then sue the factory when they succeed in doing damage.
And I am not trying to be preachy here .
I have a customer with Lupis so she can hot hold a bail for any length of time.
The solution is a pin that holds the bail closed tied to a string around her wrist so if she falls over the mower stops , not bypassing the bail all together.
So if you have the wiring diagram just follow the kill wire back from the coil to where ever it grounds, and there will be a lot of places where this can happen.
If necessary print it out a couple of times, pinch a coloured pencil from one of the kids and trace over the kill wires for each situation or use different coloured wires for PTO on & PTO off
IF there is no pin out for the PTO switch then pull it out and measure across the contacts.
It is a simple sliding contact switch that connects left to right and generally all of the middle row will be tied together.
#10
L
Luffydog
L
Luffydog
Put everything back in place all safety switches and see if the problem goes away. Also at 3.3 ohms is high for the clutch so soon as you apply the clutch it draws out all the battery and could be your problem. Replace the safety's then go from there one leads go to the others failure.
#11
Richie F
I was thinking of putting a switch in line to the Mag but would like to find the reason for the problem first.
Richie F
Simple solution would be to put a momentary contact switch on the mag. kill line to ground. No big voltage or current in this circuit. Bypass all the stuff. Nice big red button on the dash. Probably not legal in all 50 states though.
I was thinking of putting a switch in line to the Mag but would like to find the reason for the problem first.
#12
Richie F
I'm using a VOM. That's what I used to check the diode that goes to negative lead of the clutch.
Richie F
I would use an OHM meter and find what is connecting the kill wire to ground to kill the engine when pto switch is pulled to engage the clutch.
I'm using a VOM. That's what I used to check the diode that goes to negative lead of the clutch.
#13
Richie F
Please read my first post, last sentence.
Richie F
a wiring diagram is can be found on partstree under the model and serial number for that machine
Please read my first post, last sentence.
#14
Richie F
My friend owns a lawn service and worked very late Thursday. Didn't get to do what you have suggested.
Wanted to first verify all switches and then hook everything back up.
I thought the ohm range for a clutch was 2 to 4 ohms.
This is a walk behind that doesn't have a battery, only has a rectifier to supply voltage.
I should measure it and see its output though. Then find a spec on it.
Richie F
Put everything back in place all safety switches and see if the problem goes away. Also at 3.3 ohms is high for the clutch so soon as you apply the clutch it draws out all the battery and could be your problem. Replace the safety's then go from there one leads go to the others failure.
My friend owns a lawn service and worked very late Thursday. Didn't get to do what you have suggested.
Wanted to first verify all switches and then hook everything back up.
I thought the ohm range for a clutch was 2 to 4 ohms.
This is a walk behind that doesn't have a battery, only has a rectifier to supply voltage.
I should measure it and see its output though. Then find a spec on it.
#15
Richie F
"As you might have already guessed I do not have much time for people disabling safety switches"
I wasn't aware of this.
I have used the wiring diagram to trace out the Mag wire circuit. That's where I found the 600v/6a diode in the ground lead from the clutch. Thought it could have been bad and when I checked its directions it showed good.
My friend has another identical machine with the safeties by passed and it operates with no problems. Start it up and engage the blades and it doesn't shut down.
Richie F
In which case my first reply is still valid, the PTO switch will have several safety circuits running through it and they are very difficult for people with no idea about what they are doing or basic DC electronics to bypass properly.
As you might have already guessed I do not have much time for people disabling safety switches
So if you have the wiring diagram just follow the kill wire back from the coil to where ever it grounds, and there will be a lot of places where this can happen.
If necessary print it out a couple of times, pinch a coloured pencil from one of the kids and trace over the kill wires for each situation or use different coloured wires for PTO on & PTO off
IF there is no pin out for the PTO switch then pull it out and measure across the contacts.
It is a simple sliding contact switch that connects left to right and generally all of the middle row will be tied together.
"As you might have already guessed I do not have much time for people disabling safety switches"
I wasn't aware of this.
I have used the wiring diagram to trace out the Mag wire circuit. That's where I found the 600v/6a diode in the ground lead from the clutch. Thought it could have been bad and when I checked its directions it showed good.
My friend has another identical machine with the safeties by passed and it operates with no problems. Start it up and engage the blades and it doesn't shut down.
#16
B
bertsmobile1
B
bertsmobile1
It will be in the PTO switch.
There should be a kill wire that is active when whatever it uses to work out you are not deceased is in the "no one is here mode"
There should be a kill wire that is active when whatever it uses to work out you are not deceased is in the "no one is here mode"
#17
Richie F
"It will be in the PTO switch."
If you are talking about the diode, it is in the harness not the switch.
"There should be a kill wire that is active when whatever it uses to work out you are not deceased is in the "no one is here mode"
Could you write this differently ? Really don't understand what your trying to say.
Richie F
It will be in the PTO switch.
There should be a kill wire that is active when whatever it uses to work out you are not deceased is in the "no one is here mode"
"It will be in the PTO switch."
If you are talking about the diode, it is in the harness not the switch.
"There should be a kill wire that is active when whatever it uses to work out you are not deceased is in the "no one is here mode"
Could you write this differently ? Really don't understand what your trying to say.
#18
Richie F
Richie F
Here is the wiring for this machine.
https://www.partstree.com/models/sw...kawasaki-sn-j6100001-j6199999/wire-harness-9/
Going to contact SCAG at 1-800-937-7279 to ask them what the switch function is in the circuit.
Are they all NO (Normally Open) or are some NC (Normally Closed).
That will help in tracing out the ground circuit.
https://www.partstree.com/models/sw...kawasaki-sn-j6100001-j6199999/wire-harness-9/
Going to contact SCAG at 1-800-937-7279 to ask them what the switch function is in the circuit.
Are they all NO (Normally Open) or are some NC (Normally Closed).
That will help in tracing out the ground circuit.
#19
Richie F
Richie F
This getting interesting.
Just talked the SCAG.
They said there is a safety in the CONNECTOR PLUG for the operator presence switch. If that plug is not on the switch itself it can cause a ground to the Mag when the PTO is engaged.
The person also said there is a safety built into the PTO switch, but couldn't tell me how to test it.
The rectifier puts out AC voltage not DC like you think it would.
I said it's a rectifier. Its job is to change AC to DC like the alternator on your car. The person said "That's the way it works"
So why is it if you put 12V to the clutch coil to test it, it works. The answer given "Your fooling the clutch"
I have a bad taste in my mouth about parts of this conversation.
I'll get back when I look at both parts.
Just talked the SCAG.
They said there is a safety in the CONNECTOR PLUG for the operator presence switch. If that plug is not on the switch itself it can cause a ground to the Mag when the PTO is engaged.
The person also said there is a safety built into the PTO switch, but couldn't tell me how to test it.
The rectifier puts out AC voltage not DC like you think it would.
I said it's a rectifier. Its job is to change AC to DC like the alternator on your car. The person said "That's the way it works"
So why is it if you put 12V to the clutch coil to test it, it works. The answer given "Your fooling the clutch"
I have a bad taste in my mouth about parts of this conversation.
I'll get back when I look at both parts.
#20
B
bertsmobile1
B
bertsmobile1
I was going to leave this alone because of the belief that if you can not work out how to bypass things that are there for your own safety then you should leave them alone.
If understanding how they work is beyond you mental capacity then operating the machine safely is probably beyond your mental capacity as well.
None of them will stop you using the machine to it's full capacity if they are working and there is no real reason to bypass them.
The pto switch should be shown in the wiring diagram.
They are generally shown turned off so you continuity test them off and then on then go back to the wiring diagram.
It is a switch so some pairs will be open & some will be closed depending upon which position the switch is in and I have already told you it switches left to right and if it is a 3 row switch the middle ones are all connected together.
As for the operator presence switch plug, that is common now days to prevent the red neck, brain dead simply unplugging one then getting injured.
The reason is because some idiot moron bastards pulled them out , got hurt, then got massive damages payments by convincing a judge that it is possible for the plug to "fall out " without the operator knowing it.
So a simple plug that was cheap & easily available became very expensive & very hard to get one
Some companies have gone the other way by making safety switch a normally closed switch.
If you thought that a Scag employee or dealer was going to tell some one over the phone how to bypass the safety features, many of which are a legal requirement, then you must be incapable of reason.
The factory fits safety equipment then I tell you have to defeat it, you get hurt then I have left myself open to a massive law suit.
So naturally they will not tell you how to do it, not unless they are barking mad.
They might have told you how to test the various parts are working but that would be the limit of what a reasonable person would expect from them.
And you are yet to divulge why it is vitally important that your friend gets the safety switches bypassed on his mower.,
And have another thought, does his wife & children love you to the point that if he looses a hand or foot using the mower that you made "legally unsafe to operate", none of them will yield to the ambulance chasing lawers promising them they can get millions from you & Scag in compensation ?
How strong do you think your friendship is ?
lots of folks in the poor house because a close & trusted friend was not quite as close when an oppertunity to make a big amount of money presented itself.
If understanding how they work is beyond you mental capacity then operating the machine safely is probably beyond your mental capacity as well.
None of them will stop you using the machine to it's full capacity if they are working and there is no real reason to bypass them.
The pto switch should be shown in the wiring diagram.
They are generally shown turned off so you continuity test them off and then on then go back to the wiring diagram.
It is a switch so some pairs will be open & some will be closed depending upon which position the switch is in and I have already told you it switches left to right and if it is a 3 row switch the middle ones are all connected together.
As for the operator presence switch plug, that is common now days to prevent the red neck, brain dead simply unplugging one then getting injured.
The reason is because some idiot moron bastards pulled them out , got hurt, then got massive damages payments by convincing a judge that it is possible for the plug to "fall out " without the operator knowing it.
So a simple plug that was cheap & easily available became very expensive & very hard to get one
Some companies have gone the other way by making safety switch a normally closed switch.
If you thought that a Scag employee or dealer was going to tell some one over the phone how to bypass the safety features, many of which are a legal requirement, then you must be incapable of reason.
The factory fits safety equipment then I tell you have to defeat it, you get hurt then I have left myself open to a massive law suit.
So naturally they will not tell you how to do it, not unless they are barking mad.
They might have told you how to test the various parts are working but that would be the limit of what a reasonable person would expect from them.
And you are yet to divulge why it is vitally important that your friend gets the safety switches bypassed on his mower.,
And have another thought, does his wife & children love you to the point that if he looses a hand or foot using the mower that you made "legally unsafe to operate", none of them will yield to the ambulance chasing lawers promising them they can get millions from you & Scag in compensation ?
How strong do you think your friendship is ?
lots of folks in the poor house because a close & trusted friend was not quite as close when an oppertunity to make a big amount of money presented itself.
#21
L
Luffydog
L
Luffydog
Because the clutch is dc not ac. Like everyone has said put it back like new and give it a go and see what happens. If things doesn't work correctly as far as the safety then one of the safety's are bad and yes that might include the pto switch being bad. Meaning if your mower starts and run correctly then after heating up and you decide to stop and get a drink or get off the mower for a pick up and it quits meaning pto switch doesn't realize that the blades are off and kills the mower. If you stop you turn off the engine and rest then you go back out and the mower doesn't start although the switch is it doesn't realize the clutch is off because the switch has failed if all the others are working correctly and hooked up like they should be. Yes there is a test that can be done for most that had the safety interlock module. But really nobody can really help you if you won't listen to what is going on with the safety switches and with the life safety and personal injury. Most here are pros and dealers who deal with theses issues on a daily basis and take great pride to help others who have issues. We don't step out of bounds!!!! Hands down and hats off to Bert.
#22
Richie F
First off I am not stupid and have been in the automotive field for over 50 years.
Second I only called SCAG to ask the function of the switches, the conversation drifted as we talked. Their wiring schematic does not explain this like other schematics I have looked at.
Third I agree that all switches should in place.
Forth I feel you should get off your high horse and just stay within my first post question. Don't start drow beating someone you don't even know.
Richie F
I was going to leave this alone because of the belief that if you can not work out how to bypass things that are there for your own safety then you should leave them alone.
If understanding how they work is beyond you mental capacity then operating the machine safely is probably beyond your mental capacity as well.
None of them will stop you using the machine to it's full capacity if they are working and there is no real reason to bypass them.
The pto switch should be shown in the wiring diagram.
They are generally shown turned off so you continuity test them off and then on then go back to the wiring diagram.
It is a switch so some pairs will be open & some will be closed depending upon which position the switch is in and I have already told you it switches left to right and if it is a 3 row switch the middle ones are all connected together.
As for the operator presence switch plug, that is common now days to prevent the red neck, brain dead simply unplugging one then getting injured.
The reason is because some idiot moron bastards pulled them out , got hurt, then got massive damages payments by convincing a judge that it is possible for the plug to "fall out " without the operator knowing it.
So a simple plug that was cheap & easily available became very expensive & very hard to get one
Some companies have gone the other way by making safety switch a normally closed switch.
If you thought that a Scag employee or dealer was going to tell some one over the phone how to bypass the safety features, many of which are a legal requirement, then you must be incapable of reason.
The factory fits safety equipment then I tell you have to defeat it, you get hurt then I have left myself open to a massive law suit.
So naturally they will not tell you how to do it, not unless they are barking mad.
They might have told you how to test the various parts are working but that would be the limit of what a reasonable person would expect from them.
And you are yet to divulge why it is vitally important that your friend gets the safety switches bypassed on his mower.,
And have another thought, does his wife & children love you to the point that if he looses a hand or foot using the mower that you made "legally unsafe to operate", none of them will yield to the ambulance chasing lawers promising them they can get millions from you & Scag in compensation ?
How strong do you think your friendship is ?
lots of folks in the poor house because a close & trusted friend was not quite as close when an oppertunity to make a big amount of money presented itself.
First off I am not stupid and have been in the automotive field for over 50 years.
Second I only called SCAG to ask the function of the switches, the conversation drifted as we talked. Their wiring schematic does not explain this like other schematics I have looked at.
Third I agree that all switches should in place.
Forth I feel you should get off your high horse and just stay within my first post question. Don't start drow beating someone you don't even know.
#23
Richie F
"Because the clutch is dc not ac. "
That's what I said to SCAG. The person said the rectifier is AC not DC. So how can it being AC, power the clutch, it can't. A rectifier is the part that changes AC to DC. You have a single phase stator that is AC.
Again I agree with putting everything back, but just for general knowledge I want to know the correct function of the switches so when I test them I can say this switch is good I'll now hook it up.
Richie F
Because the clutch is dc not ac. Like everyone has said put it back like new and give it a go and see what happens. If things doesn't work correctly as far as the safety then one of the safety's are bad and yes that might include the pto switch being bad. Meaning if your mower starts and run correctly then after heating up and you decide to stop and get a drink or get off the mower for a pick up and it quits meaning pto switch doesn't realize that the blades are off and kills the mower. If you stop you turn off the engine and rest then you go back out and the mower doesn't start although the switch is it doesn't realize the clutch is off because the switch has failed if all the others are working correctly and hooked up like they should be. Yes there is a test that can be done for most that had the safety interlock module. But really nobody can really help you if you won't listen to what is going on with the safety switches and with the life safety and personal injury. Most here are pros and dealers who deal with theses issues on a daily basis and take great pride to help others who have issues. We don't step out of bounds!!!! Hands down and hats off to Bert.
"Because the clutch is dc not ac. "
That's what I said to SCAG. The person said the rectifier is AC not DC. So how can it being AC, power the clutch, it can't. A rectifier is the part that changes AC to DC. You have a single phase stator that is AC.
Again I agree with putting everything back, but just for general knowledge I want to know the correct function of the switches so when I test them I can say this switch is good I'll now hook it up.
#24
tom3
tom3
Might consider the person you talked to at Scag probably doesn't know a wrench from a screwdriver. When you ask a question the answer pops up on a screen. The term rectifier probably comes up with a part number and price so he's winging it, has no clue.
#25
Richie F
Thank you. That's what I was implying about the conversation with the person.
Richie F
Might consider the person you talked to at Scag probably doesn't know a wrench from a screwdriver. When you ask a question the answer pops up on a screen. The term rectifier probably comes up with a part number and price so he's winging it, has no clue.
Thank you. That's what I was implying about the conversation with the person.
#26
NorthBama
NorthBama
Most pto switches have 3 terminals right to left and marked ( NC) normally closed (NO) normally open and (COM) for common to both normally open and normally closed. some have one row that may have only 2 terminals
#27
B
bertsmobile1
B
bertsmobile1
If you can not work out this wiring diagram then I can not be of any help to you.
https://www.jackssmallengines.com/jacks-parts-lookup/manufacturer/scag/walk-behinds/sw36a-14fs-walk-behind-s-n-j6100001-j6199999/sw-electrical-schematic-recoil-start
As previously mentioned if some one needs instructions to the level of "Join the pink wire to the green wire and cut the blue one just past the yellow wire junction" , they should not be touching the wiring.
The wiring diagram is not hard to find and it has the PTO switch connections on it.
It is a standard 3 row 8 pin plug. The terminals closest to the dash are not used because they are the pass through terminals for the starter motor that you do not have
I really can not see what your problem is , the wiring diagram is clear as crystal.
https://www.jackssmallengines.com/jacks-parts-lookup/manufacturer/scag/walk-behinds/sw36a-14fs-walk-behind-s-n-j6100001-j6199999/sw-electrical-schematic-recoil-start
As previously mentioned if some one needs instructions to the level of "Join the pink wire to the green wire and cut the blue one just past the yellow wire junction" , they should not be touching the wiring.
The wiring diagram is not hard to find and it has the PTO switch connections on it.
It is a standard 3 row 8 pin plug. The terminals closest to the dash are not used because they are the pass through terminals for the starter motor that you do not have
I really can not see what your problem is , the wiring diagram is clear as crystal.
#28
Richie F
Thank you for this information.
I do understand what NO, NC and COM means.
Have looked on YouTube to get a background on how this switch functions on a lawn mower that uses it.
Richie F
Most pto switches have 3 terminals right to left and marked ( NC) normally closed (NO) normally open and (COM) for common to both normally open and normally closed. some have one row that may have only 2 terminalsView attachment 45167
Thank you for this information.
I do understand what NO, NC and COM means.
Have looked on YouTube to get a background on how this switch functions on a lawn mower that uses it.
#29
B
bertsmobile1
NO THIS IS NOT A WIRING DIAGRAM IT IS A HARNESS LAY OUT DIAGRAM>
IF YOU HAD PUT THIS LINK UP FROM THE GET GO SOME ONE PROBABLY WOULD HAVE NOTICED YOU WERE LOOKING AT THE WRONG DIAGRAM
This is what a wiring diagram looks like
https://www.jackssmallengines.com/jacks-parts-lookup/manufacturer/scag/walk-behinds/sw36a-14fs-walk-behind-s-n-j6100001-j6199999/sw-electrical-schematic-recoil-start
B
bertsmobile1
Here is the wiring for this machine.
https://www.partstree.com/models/sw...kawasaki-sn-j6100001-j6199999/wire-harness-9/
Going to contact SCAG at 1-800-937-7279 to ask them what the switch function is in the circuit.
Are they all NO (Normally Open) or are some NC (Normally Closed).
That will help in tracing out the ground circuit.
NO THIS IS NOT A WIRING DIAGRAM IT IS A HARNESS LAY OUT DIAGRAM>
IF YOU HAD PUT THIS LINK UP FROM THE GET GO SOME ONE PROBABLY WOULD HAVE NOTICED YOU WERE LOOKING AT THE WRONG DIAGRAM
This is what a wiring diagram looks like
https://www.jackssmallengines.com/jacks-parts-lookup/manufacturer/scag/walk-behinds/sw36a-14fs-walk-behind-s-n-j6100001-j6199999/sw-electrical-schematic-recoil-start
#30
Richie F
Bert have you not read my first post ?
I have the wiring schematic already.
What I was hoping for when I started this thread was someone who had this problem and would have told me.
Could have saved a few steps.
You keep talking to me like I'm an idiot.
No, I have not bought a highlighter marker yet to backtrack the circuit. Forgive me your lordship.
I don't need "Join the pink wire to the green wire and cut the blue one just past the yellow wire junction"
When I find the functions of the safety switches it will be very easy to trace the circuits.
I will have time today to compare the problem machine to my friends other 3 SCAG walk behind units.
There are one other 36" and two 48".
Thanks for your input.
Richie F
If you can not work out this wiring diagram then I can not be of any help to you.
As previously mentioned if some one needs instructions to the level of "Join the pink wire to the green wire and cut the blue one just past the yellow wire junction" , they should not be touching the wiring.
The wiring diagram is not hard to find and it has the PTO switch connections on it.
I can not see what your problem is
https://www.jackssmallengines.com/jacks-parts-lookup/manufacturer/scag/walk-behinds/sw36a-14fs-walk-behind-s-n-j6100001-j6199999/sw-electrical-schematic-recoil-start
Bert have you not read my first post ?
I have the wiring schematic already.
What I was hoping for when I started this thread was someone who had this problem and would have told me.
Could have saved a few steps.
You keep talking to me like I'm an idiot.
No, I have not bought a highlighter marker yet to backtrack the circuit. Forgive me your lordship.
I don't need "Join the pink wire to the green wire and cut the blue one just past the yellow wire junction"
When I find the functions of the safety switches it will be very easy to trace the circuits.
I will have time today to compare the problem machine to my friends other 3 SCAG walk behind units.
There are one other 36" and two 48".
Thanks for your input.
#31
NorthBama
I can tell by your reply that your are capable of checking this PTO switch so i wish you good results on this endeavor. Glad to hear you are helping a friend.
YouTube is my friend also
NorthBama
Thank you for this information.
I do understand what NO, NC and COM means.
Have looked on YouTube to get a background on how this switch functions on a lawn mower that uses it.
I can tell by your reply that your are capable of checking this PTO switch so i wish you good results on this endeavor. Glad to hear you are helping a friend.
YouTube is my friend also
#32
Richie F
All I can say is thank you.
Richie F
I can tell by your reply that your are capable of checking this PTO switch so i wish you good results on this endeavor. Glad to hear you are helping a friend.
YouTube is my friend also
All I can say is thank you.
#33
B
bertsmobile1
Yes I read your first post, several times
And I do appreciate that many people struggle with reading circuit diagrams.
The diagram that you put a link to in your post #18 yesterday shows THE WIRING HARNESS NOT THE CIRCUITS
When I actually checked that link I understood why you were struggling to work out the mowers wiring so I posted a link to a CIRCUIT DIAGRAM which is a totally different animal
Since then I found the rest of the diagram as the link I posted yesterday only had the engine plug to handlebar section on it.
It appears that Scag publish it in 3 different ways, engine side, handle bar side and full diagram, however the full diagram does not show the diode.
But the diode will have less than nothing to do with grounding the magneto so has less than no impact on the no spark problem, being that is is on a power wire and all magneto wires are ground wires.
So here is the full wiring diagram, it was there all along I just had not gone deep enough into the parts breakdown to find it the first time , lazy me.
When you said you had a wiring diagram this is what I assumed you were looking at.
As you were not then what I posted would have been confusing .
All of the switches in this diagram are shown in the OFF position , ie key off, no operator ( assume this is a bail handle of some sort ) and blades off .
Now the diagram is bad as the white wire which is shown as a double thin black line did not copy properly so lumps of it are missing but the important bit, which plugs & what terminals is shown so if it is confusing, just print it out & join the wires together.
And with this I am out of here.
Note the pins on the PTO switch are numbered in the diagram ( look hard ) but not all PTO switches have the pins numbers on them.
B
bertsmobile1
Bert have you not read my first post ?
I have the wiring schematic already.
What I was hoping for when I started this thread was someone who had this problem and would have told me.
Could have saved a few steps.
You keep talking to me like I'm an idiot.
No, I have not bought a highlighter marker yet to backtrack the circuit. Forgive me your lordship.
I don't need "Join the pink wire to the green wire and cut the blue one just past the yellow wire junction"
When I find the functions of the safety switches it will be very easy to trace the circuits.
I will have time today to compare the problem machine to my friends other 3 SCAG walk behind units.
There are one other 36" and two 48".
Thanks for your input.
Yes I read your first post, several times
And I do appreciate that many people struggle with reading circuit diagrams.
The diagram that you put a link to in your post #18 yesterday shows THE WIRING HARNESS NOT THE CIRCUITS
When I actually checked that link I understood why you were struggling to work out the mowers wiring so I posted a link to a CIRCUIT DIAGRAM which is a totally different animal
Since then I found the rest of the diagram as the link I posted yesterday only had the engine plug to handlebar section on it.
It appears that Scag publish it in 3 different ways, engine side, handle bar side and full diagram, however the full diagram does not show the diode.
But the diode will have less than nothing to do with grounding the magneto so has less than no impact on the no spark problem, being that is is on a power wire and all magneto wires are ground wires.
So here is the full wiring diagram, it was there all along I just had not gone deep enough into the parts breakdown to find it the first time , lazy me.
When you said you had a wiring diagram this is what I assumed you were looking at.
As you were not then what I posted would have been confusing .
All of the switches in this diagram are shown in the OFF position , ie key off, no operator ( assume this is a bail handle of some sort ) and blades off .
Now the diagram is bad as the white wire which is shown as a double thin black line did not copy properly so lumps of it are missing but the important bit, which plugs & what terminals is shown so if it is confusing, just print it out & join the wires together.
And with this I am out of here.
Note the pins on the PTO switch are numbered in the diagram ( look hard ) but not all PTO switches have the pins numbers on them.
#34
Richie F
Richie F
Thank you for the schematic.
The one I posted from Parts Tree was the same one from the Scag Parts/Maintenance manual.
I couldn't post the one from the manual because it was in PDF format.
The bottom of the new schematic at the very bottom shows the diode.
https://learn.sparkfun.com/tutorials/polarity/diode-and-led-polarity
Had time to test things yesterday also.
All three switches are NO.They are the key, operator present switch and trans neutral interlock (in neutral).
Also there is a safety in the plug connector for the operator switch. It's a spring loaded button in the middle of the two spade terminals.
When it's pressed in the wires are NO.
Both sets of terminals on the PTO switch in the off position are NC.
I hooked up all safety's and installed my VOM on the wire to the Mag wire unplugged from the engine and the other to engine ground. Used the continuity setting on the meter.
When I engage the PTO I had a ground to engine block. Showing engine will shut off.
Installed a different correct known good PTO switch from another machine and the outcome was the same.
Unplugged the connector to the clutch and had same results.
Unplugged the rectifier wire, tested the engine running and same thing.
I thought maybe the rectifier windings might have been shorted to ground.
Running out of ideas.
The one I posted from Parts Tree was the same one from the Scag Parts/Maintenance manual.
I couldn't post the one from the manual because it was in PDF format.
The bottom of the new schematic at the very bottom shows the diode.
https://learn.sparkfun.com/tutorials/polarity/diode-and-led-polarity
Had time to test things yesterday also.
All three switches are NO.They are the key, operator present switch and trans neutral interlock (in neutral).
Also there is a safety in the plug connector for the operator switch. It's a spring loaded button in the middle of the two spade terminals.
When it's pressed in the wires are NO.
Both sets of terminals on the PTO switch in the off position are NC.
I hooked up all safety's and installed my VOM on the wire to the Mag wire unplugged from the engine and the other to engine ground. Used the continuity setting on the meter.
When I engage the PTO I had a ground to engine block. Showing engine will shut off.
Installed a different correct known good PTO switch from another machine and the outcome was the same.
Unplugged the connector to the clutch and had same results.
Unplugged the rectifier wire, tested the engine running and same thing.
I thought maybe the rectifier windings might have been shorted to ground.
Running out of ideas.
#35
Richie F
Richie F
OK
Thought about this.
Going to have to test every wire in each harness to see if there is a possible short to ground from one of them.
Both harnesses don't show any damage though.
As The Terminator said "I'll be back !"
Thought about this.
Going to have to test every wire in each harness to see if there is a possible short to ground from one of them.
Both harnesses don't show any damage though.
As The Terminator said "I'll be back !"
#36
NorthBama
NorthBama
rectifier wire?
are you talking about the stater coil winding under the flywheel?
are you talking about the stater coil winding under the flywheel?
#37
Richie F
Yes.
There are two, one comes from the ignition coil and the other from the stator winding.
Stator is inside the flywheel.
Coil is on the outside of the flywheel.
Richie F
rectifier wire?
are you talking about the stater coil winding under the flywheel?
Yes.
There are two, one comes from the ignition coil and the other from the stator winding.
Stator is inside the flywheel.
Coil is on the outside of the flywheel.
#38
B
bertsmobile1
Sit down and trace out the circuits, you are not understanding how they work.
In the off position the magneto is grounded by the key switch.
In the on position the magneto is grounded by the operator switch
In the on position the magneto is grounded by the operator switch
B
bertsmobile1
Thank you for the schematic.
The one I posted from Parts Tree was the same one from the Scag Parts/Maintenance manual.
I couldn't post the one from the manual because it was in PDF format.
PDF's get posted as an attachment so they show up as a link to a downlodd URL just like to one you posted here to the electronics how to page
All three switches are NO.They are the key, operator present switch and trans neutral interlock (in neutral).
No they are not.
The key switch, in the OFF ( NORMAL ) POSITION is closed to ground the coil & kill the spark.
The operator switch is also CLOSED IN THE OFF position so it is a NC switch as well
Both sets of terminals on the PTO switch in the off position are NC.
NO again.
The PTO switch is neither NO nor NC the PTO switch moves continuity from the outside terminal to an inside terminal or visa versa.
In the top right hand corner of the diagram I posted a link to was the connections for the PTO switch which as shown in the diagram moves to connections from left to right ( as drawn ) when off to left to centre when on.
I hooked up all safety's and installed my VOM on the wire to the Mag wire unplugged from the engine and the other to engine ground. Used the continuity setting on the meter.
When I engage the PTO I had a ground to engine block. Showing engine will shut off.
Installed a different correct known good PTO switch from another machine and the outcome was the same.
Unplugged the connector to the clutch and had same results.
Unplugged the rectifier wire, tested the engine running and same thing.
I thought maybe the rectifier windings might have been shorted to ground.
Running out of ideas.
Sit down and trace out the circuits, you are not understanding how they work.
In the off position the magneto is grounded by the key switch.
In the on position the magneto is grounded by the operator switch
In the on position the magneto is grounded by the operator switch
#39
Richie F
OK will look into this.
Have printed out the schematic you posted also and will study it this morning.
Richie F
Sit down and trace out the circuits, you are not understanding how they work.
In the off position the magneto is grounded by the key switch.
In the on position the magneto is grounded by the operator switch
In the on position the magneto is grounded by the operator switch
OK will look into this.
Have printed out the schematic you posted also and will study it this morning.
#40
T
Telesis
T
Telesis
The purpose of this message is to (hopefully) provide some clarification with respect to the comments about diodes, rectifiers, AC and DC. You noted correctly before that the voltage coming from the stator of the engine is AC. Some stator assemblies incorporate a single diode in the harness to provide 'half-wave rectified' AC to the rest of the machine. Some older engines incorporate two individually replaceable diodes to do 'full-wave rectification' of the AC to the rest of the machine. Some embed two in a harness. I'm pretty sure that your Scag's Kawasaki engine uses a 3 terminal 'voltage regulator' to convert the AC stator voltage to the DC used by the machine. AC from the stator goes 'into' the regulator on the two terminals labeled AC, and the rectified or DC output comes from the terminal labeled B+, and ground. I'm pretty sure the wire labeled 'rectifier' on the diagram goes to that B+ terminal of the voltage regulator on the engine.
So, what's the purpose of the diode located across the PTO coil? Well it's merely there to provide protection to the regulator located on the engine. It has absolutely nothing to do with converting AC to DC for operating the PTO. It's called a 'flyback' diode. Why is it needed? Whenever a DC current is flowing through a coil, and it is interrupted by the opening of the PTO switch, it creates a huge voltage spike across the coil. I won't bore you with the engineering reason why. That voltage spike can damage the regulator on the engine because it 'sees' or is exposed to the spike. The semiconductor devices embedded in the voltage regulator can be damaged by this kind of high voltage spike. The diode across the PTO coil absorbs the spike by providing an electrical path around the coil, and the regulator on the engine never 'sees' the spike. The fact of the matter is that it is NOT required to operate the PTO. You can disconnect it and operate the PTO just fine. The chance you take is you damage the regulator when you open the PTO. Many machines don't use a flyback protection diode, particularly ones that have batteries. A battery also absorbs that spike. Under normal operating conditions(PTO on), the voltage present on the cathode side of the diode is always positive with respect to the anode and as a result, there is NO current flowing through the diode. That's why it's not necessary for the operation of the PTO. It's for protection only.
I know you said you checked the diode, but understand if this diode were shorted, it could produce the condition you are seeing. I'd still suggest the following quick test. Disconnect one leg of the diode and then start it. Hit the PTO and see if it still kills it. BTW, the chances of this one test causing damage to the engine voltage regulator are very small. That device is robust and it's the repeated exposure to voltage spikes that causes semiconductor breakdown leading to part failure.
FWIW... Let us know how you make out!
So, what's the purpose of the diode located across the PTO coil? Well it's merely there to provide protection to the regulator located on the engine. It has absolutely nothing to do with converting AC to DC for operating the PTO. It's called a 'flyback' diode. Why is it needed? Whenever a DC current is flowing through a coil, and it is interrupted by the opening of the PTO switch, it creates a huge voltage spike across the coil. I won't bore you with the engineering reason why. That voltage spike can damage the regulator on the engine because it 'sees' or is exposed to the spike. The semiconductor devices embedded in the voltage regulator can be damaged by this kind of high voltage spike. The diode across the PTO coil absorbs the spike by providing an electrical path around the coil, and the regulator on the engine never 'sees' the spike. The fact of the matter is that it is NOT required to operate the PTO. You can disconnect it and operate the PTO just fine. The chance you take is you damage the regulator when you open the PTO. Many machines don't use a flyback protection diode, particularly ones that have batteries. A battery also absorbs that spike. Under normal operating conditions(PTO on), the voltage present on the cathode side of the diode is always positive with respect to the anode and as a result, there is NO current flowing through the diode. That's why it's not necessary for the operation of the PTO. It's for protection only.
I know you said you checked the diode, but understand if this diode were shorted, it could produce the condition you are seeing. I'd still suggest the following quick test. Disconnect one leg of the diode and then start it. Hit the PTO and see if it still kills it. BTW, the chances of this one test causing damage to the engine voltage regulator are very small. That device is robust and it's the repeated exposure to voltage spikes that causes semiconductor breakdown leading to part failure.
FWIW... Let us know how you make out!
#41
Richie F
OK thanks for some education on this problem.
If you look at either wiring diagram/schematic posted you will only find one diode in the harness to the clutch.
From the parts break down of the Kawasaki FS481V engine there is only a one wire stator with no 3 terminal voltage regulator.
https://www.jackssmallengines.com/j...s22-4-stroke-engine-fs481v/electric-equipment
So the diode should be a fly back?
This is the way I tested it:
Engine not running.
Disconnected the deck harness plug to the handle switches.
Unplug the connector at the clutch, using my VOM set on the diode symbol, tested the two wires on that plug. Went from A to B one way and it was OL. Changed leads on A and B and got zero volts, showing a voltage path.
I would think if that diode was shorted I would see zero volts in both directions.
Correct me if I'm wrong.
This machine is a pull start and does not have a battery or starter motor.
I'm curious how a single wire wound stator can produce a DC voltage to operate the electric clutch with no regulator ?
I want to make a break out T and see what the output will be. AC or DC.
I do have a sister machine with no problems. I can test it's single diode or install that deck harness on to the problem unit.
I'll leave you with this information.
Richie F
The purpose of this message is to (hopefully) provide some clarification with respect to the comments about diodes, rectifiers, AC and DC. You noted correctly before that the voltage coming from the stator of the engine is AC. Some stator assemblies incorporate a single diode in the harness to provide 'half-wave rectified' AC to the rest of the machine. Some older engines incorporate two individually replaceable diodes to do 'full-wave rectification' of the AC to the rest of the machine. Some embed two in a harness. I'm pretty sure that your Scag's Kawasaki engine uses a 3 terminal 'voltage regulator' to convert the AC stator voltage to the DC used by the machine. AC from the stator goes 'into' the regulator on the two terminals labeled AC, and the rectified or DC output comes from the terminal labeled B+, and ground. I'm pretty sure the wire labeled 'rectifier' on the diagram goes to that B+ terminal of the voltage regulator on the engine.
So, what's the purpose of the diode located across the PTO coil? Well it's merely there to provide protection to the regulator located on the engine. It has absolutely nothing to do with converting AC to DC for operating the PTO. It's called a 'flyback' diode. Why is it needed? Whenever a DC current is flowing through a coil, and it is interrupted by the opening of the PTO switch, it creates a huge voltage spike across the coil. I won't bore you with the engineering reason why. That voltage spike can damage the regulator on the engine because it 'sees' or is exposed to the spike. The semiconductor devices embedded in the voltage regulator can be damaged by this kind of high voltage spike. The diode across the PTO coil absorbs the spike by providing an electrical path around the coil, and the regulator on the engine never 'sees' the spike. The fact of the matter is that it is NOT required to operate the PTO. You can disconnect it and operate the PTO just fine. The chance you take is you damage the regulator when you open the PTO. Many machines don't use a flyback protection diode, particularly ones that have batteries. A battery also absorbs that spike. Under normal operating conditions(PTO on), the voltage present on the cathode side of the diode is always positive with respect to the anode and as a result, there is NO current flowing through the diode. That's why it's not necessary for the operation of the PTO. It's for protection only.
I know you said you checked the diode, but understand if this diode were shorted, it could produce the condition you are seeing. I'd still suggest the following quick test. Disconnect one leg of the diode and then start it. Hit the PTO and see if it still kills it. BTW, the chances of this one test causing damage to the engine voltage regulator are very small. That device is robust and it's the repeated exposure to voltage spikes that causes semiconductor breakdown leading to part failure.
FWIW... Let us know how you make out!
OK thanks for some education on this problem.
If you look at either wiring diagram/schematic posted you will only find one diode in the harness to the clutch.
From the parts break down of the Kawasaki FS481V engine there is only a one wire stator with no 3 terminal voltage regulator.
https://www.jackssmallengines.com/j...s22-4-stroke-engine-fs481v/electric-equipment
So the diode should be a fly back?
This is the way I tested it:
Engine not running.
Disconnected the deck harness plug to the handle switches.
Unplug the connector at the clutch, using my VOM set on the diode symbol, tested the two wires on that plug. Went from A to B one way and it was OL. Changed leads on A and B and got zero volts, showing a voltage path.
I would think if that diode was shorted I would see zero volts in both directions.
Correct me if I'm wrong.
This machine is a pull start and does not have a battery or starter motor.
I'm curious how a single wire wound stator can produce a DC voltage to operate the electric clutch with no regulator ?
I want to make a break out T and see what the output will be. AC or DC.
I do have a sister machine with no problems. I can test it's single diode or install that deck harness on to the problem unit.
I'll leave you with this information.
#42
T
Telesis
T
Telesis
Yes, I see, this engine does not use a regulator(being that it's a recoil start model). Here is a link to the engine service manual:
http://kawasaki.com/kengine/engines...094-01_fs600v_fs541v_fs481v_english-ebook.pdf
It's interesting that the service manual does not spec an AC output, rather just a stator coil resistance of 4.4 to 15 ohms for the recoil start model (see p 9-6). I do not believe a diode is embedded in the single wire output of the stator coil(if it was they would have a different procedure at the bottom of page 9-17 on testing the coil resistance) So, one side of the stator coil is grounded and the other is brought out via the single lead. That means there's another diode or rectifier somewhere. What's not clear to me based on the wiring diagram from Berts is where the yellow wire labeled 'rectifier' plugs into. Also, it's possible the rectifier diode is what is being depicted at the end of that yellow wire and that plugs into the stator output, point A in the bottom picture on page 9-17. Perfect place for it.
Normally(if there is such a thing), when you test a diode using a VOM on the 'diode' setting, a good diode will read the voltage drop when the diode is forward biased (red on anode, black on cathode) and the value is typically 0.2 - 0.7 VDC. In the opposite direction, the meter will read as an open circuit (typically a '1' or 'OL' , same reading with leads disconnected from diode). A shorted diode will read 0 VDC in both directions. You should double check you don't have 0 VDC in both directions, which would indicate a shorted diode and cause the problem you are having. In addition to testing it on the 'diode' function of the meter, please test it using the Ohms or resistance function. Measure the resistance in both directions. Let us know what you find.
Let us know!
http://kawasaki.com/kengine/engines...094-01_fs600v_fs541v_fs481v_english-ebook.pdf
It's interesting that the service manual does not spec an AC output, rather just a stator coil resistance of 4.4 to 15 ohms for the recoil start model (see p 9-6). I do not believe a diode is embedded in the single wire output of the stator coil(if it was they would have a different procedure at the bottom of page 9-17 on testing the coil resistance) So, one side of the stator coil is grounded and the other is brought out via the single lead. That means there's another diode or rectifier somewhere. What's not clear to me based on the wiring diagram from Berts is where the yellow wire labeled 'rectifier' plugs into. Also, it's possible the rectifier diode is what is being depicted at the end of that yellow wire and that plugs into the stator output, point A in the bottom picture on page 9-17. Perfect place for it.
Normally(if there is such a thing), when you test a diode using a VOM on the 'diode' setting, a good diode will read the voltage drop when the diode is forward biased (red on anode, black on cathode) and the value is typically 0.2 - 0.7 VDC. In the opposite direction, the meter will read as an open circuit (typically a '1' or 'OL' , same reading with leads disconnected from diode). A shorted diode will read 0 VDC in both directions. You should double check you don't have 0 VDC in both directions, which would indicate a shorted diode and cause the problem you are having. In addition to testing it on the 'diode' function of the meter, please test it using the Ohms or resistance function. Measure the resistance in both directions. Let us know what you find.
Let us know!
#43
Richie F
Thanks for the engine manual. I didn't have that one.
As far as the single diode is concerned if you look at Berts schematic, on the bottom by the clutch winding symbol you will see the diode.
I must have tested this diode incorrectly.
Using the VOM on it, one way was OL and the other 0 volts.
As far as the rectifier wire goes, look at the other diagram posted by me from Parts Tree.
That yellow wire goes from rectifier to PTO switch. From switch to goes directly to the positive side of the clutch coil.
Richie F
Yes, I see, this engine does not use a regulator(being that it's a recoil start model). Here is a link to the engine service manual:
http://kawasaki.com/kengine/engines...094-01_fs600v_fs541v_fs481v_english-ebook.pdf
It's interesting that the service manual does not spec an AC output, rather just a stator coil resistance of 4.4 to 15 ohms for the recoil start model (see p 9-6). I do not believe a diode is embedded in the single wire output of the stator coil(if it was they would have a different procedure at the bottom of page 9-17 on testing the coil resistance) So, one side of the stator coil is grounded and the other is brought out via the single lead. That means there's another diode or rectifier somewhere. What's not clear to me based on the wiring diagram from Berts is where the yellow wire labeled 'rectifier' plugs into. Also, it's possible the rectifier diode is what is being depicted at the end of that yellow wire and that plugs into the stator output, point A in the bottom picture on page 9-17. Perfect place for it.
Normally(if there is such a thing), when you test a diode using a VOM on the 'diode' setting, a good diode will read the voltage drop when the diode is forward biased (red on anode, black on cathode) and the value is typically 0.2 - 0.7 VDC. In the opposite direction, the meter will read as an open circuit (typically a '1' or 'OL' , same reading with leads disconnected from diode). A shorted diode will read 0 VDC in both directions. You should double check you don't have 0 VDC in both directions, which would indicate a shorted diode and cause the problem you are having. In addition to testing it on the 'diode' function of the meter, please test it using the Ohms or resistance function. Measure the resistance in both directions. Let us know what you find.
Let us know!
Thanks for the engine manual. I didn't have that one.
As far as the single diode is concerned if you look at Berts schematic, on the bottom by the clutch winding symbol you will see the diode.
I must have tested this diode incorrectly.
Using the VOM on it, one way was OL and the other 0 volts.
As far as the rectifier wire goes, look at the other diagram posted by me from Parts Tree.
That yellow wire goes from rectifier to PTO switch. From switch to goes directly to the positive side of the clutch coil.
#44
Richie F
Richie F
The more I look at the wiring I'm prone to think that one diode is the problem.
Current comes from rectifier thru PTO to the positive side of the clutch coil.
The diode prevents current to go directly to ground.
If that diode is shorted rectifier current goes to ground and shutting off the engine.
The mag wire is on the same terminal as the ground wire at the main harness plug. Which is terminal C
Blue wire of clutch goes to black wire ground.
Black wire ground is connected to white wire mag.
Grounding mag wire.
Engine shuts off when turning on PTO for the blades.
Then again I could be missing the boat on this.
Current comes from rectifier thru PTO to the positive side of the clutch coil.
The diode prevents current to go directly to ground.
If that diode is shorted rectifier current goes to ground and shutting off the engine.
The mag wire is on the same terminal as the ground wire at the main harness plug. Which is terminal C
Blue wire of clutch goes to black wire ground.
Black wire ground is connected to white wire mag.
Grounding mag wire.
Engine shuts off when turning on PTO for the blades.
Then again I could be missing the boat on this.
#45
T
Telesis
T
Telesis
OK, you are going to love me for this one. I should have done this sooner, and that is read all previous posts several times and print out all the stuff. I mistakenly said earlier that a shorted flyback diode(the one by the clutch) could cause your problem and I was wrong. After printing out the pretty colored schematic on p17 of the SCAG IPL for this unit, the two circuits(1-stator, rectifier, clutch and 2-key sw,operator sw, PTO sw, neutral interlock sw, magneto) are totally independent. If the flyback diode was shorted, that isn't going to kill the spark. My bad. My apologies to the forum.
In one of your previous posts, you identified the symptom when you measured the resistance of the magneto wire(at the engine) to ground and turned on the PTO switch. You found that there was continuity! I'm assuming you had the operator present switch(es) engaged, tranny in neutral, the key switch was ON, and you turned(or pulled) the PTO switch ON. If you have continuity, that's not OK and the magneto is grounded. You should not have continuity with the PTO in either position(when all is OK)!
This is what the "PTO Switch Legend" tells you. When the PTO switch is OFF, H is connected to F which is a 'don't care' because terminal F is unused. C is connected to D which is also a 'don't care' because neither is used. When the PTO is ON, B is connected to C which is another 'don't care' because neither is used. G connects to H which is part of the magneto circuit, and E connects to A which is part of the clutch circuit. Think of the PTO switch(in this instance) as a double-pole single-throw switch.
Berts statements are spot on:
In the off position the magneto is grounded by the key switch.
In the on position the magneto is grounded by the operator switch
In the on position the magneto is grounded by the operator switch
I'd add that in the off position the magneto is grounded by the operator switch if the tranny is NOT in neutral
Sorry for taking you(et.al.) down the flyback diode road. The purpose of that diode and how to test it are still accurate. My recommendation is to go "sniffing" around the operator switch(s) and make sure they are OK(opening up properly). Trace it out as Berts said. There is a very manageable number of wires here. Could be much worse!
In one of your previous posts, you identified the symptom when you measured the resistance of the magneto wire(at the engine) to ground and turned on the PTO switch. You found that there was continuity! I'm assuming you had the operator present switch(es) engaged, tranny in neutral, the key switch was ON, and you turned(or pulled) the PTO switch ON. If you have continuity, that's not OK and the magneto is grounded. You should not have continuity with the PTO in either position(when all is OK)!
This is what the "PTO Switch Legend" tells you. When the PTO switch is OFF, H is connected to F which is a 'don't care' because terminal F is unused. C is connected to D which is also a 'don't care' because neither is used. When the PTO is ON, B is connected to C which is another 'don't care' because neither is used. G connects to H which is part of the magneto circuit, and E connects to A which is part of the clutch circuit. Think of the PTO switch(in this instance) as a double-pole single-throw switch.
Berts statements are spot on:
In the off position the magneto is grounded by the key switch.
In the on position the magneto is grounded by the operator switch
In the on position the magneto is grounded by the operator switch
I'd add that in the off position the magneto is grounded by the operator switch if the tranny is NOT in neutral
Sorry for taking you(et.al.) down the flyback diode road. The purpose of that diode and how to test it are still accurate. My recommendation is to go "sniffing" around the operator switch(s) and make sure they are OK(opening up properly). Trace it out as Berts said. There is a very manageable number of wires here. Could be much worse!
#46
B
bertsmobile1
If you can i would be of great benefit if you could go back to your previous post and edit out the incorrect information.
There are a lot of people who lurk and never post when they have a problem.
This post is getting very confusing when as you know the circuitry is high school science simple .
It is a sad & sorry state that people look at a wiiring diagram and their brains go to mush when they are so simple it is not funny.
B
bertsmobile1
OK, you are going to love me for this one. I should have done this sooner, and that is read all previous posts several times and print out all the stuff. I mistakenly said earlier that a shorted flyback diode(the one by the clutch) could cause your problem and I was wrong. After printing out the pretty colored schematic on p17 of the SCAG IPL for this unit, the two circuits(1-stator, rectifier, clutch and 2-key sw,operator sw, PTO sw, neutral interlock sw, magneto) are totally independent. If the flyback diode was shorted, that isn't going to kill the spark. My bad. My apologies to the forum.
In one of your previous posts, you identified the symptom when you measured the resistance of the magneto wire(at the engine) to ground and turned on the PTO switch. You found that there was continuity! I'm assuming you had the operator present switch(es) engaged, tranny in neutral, the key switch was ON, and you turned(or pulled) the PTO switch ON. If you have continuity, that's not OK and the magneto is grounded. You should not have continuity with the PTO in either position(when all is OK)!
This is what the "PTO Switch Legend" tells you. When the PTO switch is OFF, H is connected to F which is a 'don't care' because terminal F is unused. C is connected to D which is also a 'don't care' because neither is used. When the PTO is ON, B is connected to C which is another 'don't care' because neither is used. G connects to H which is part of the magneto circuit, and E connects to A which is part of the clutch circuit. Think of the PTO switch(in this instance) as a double-pole single-throw switch.
Berts statements are spot on:
In the off position the magneto is grounded by the key switch.
In the on position the magneto is grounded by the operator switch
In the on position the magneto is grounded by the operator switch
I'd add that in the off position the magneto is grounded by the operator switch if the tranny is NOT in neutral
Sorry for taking you(et.al.) down the flyback diode road. The purpose of that diode and how to test it are still accurate. My recommendation is to go "sniffing" around the operator switch(s) and make sure they are OK(opening up properly). Trace it out as Berts said. There is a very manageable number of wires here. Could be much worse!
If you can i would be of great benefit if you could go back to your previous post and edit out the incorrect information.
There are a lot of people who lurk and never post when they have a problem.
This post is getting very confusing when as you know the circuitry is high school science simple .
It is a sad & sorry state that people look at a wiiring diagram and their brains go to mush when they are so simple it is not funny.
#47
mwilliams199
mwilliams199
THIS POST IS REALLY OLD BUT MAY KNOW THE ANSWER TO MY QUESTION, DOES THE PTO SWITCH HAVE TO BE GROUNDED TO THE BLOCK WITH NO OTHER SWITCHES IN PLAY?