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How does my solenoid work? Unable to start.

#1

J

John Ambrosia

I have a Scag Turf Tiger, model # STT61V-29DFI-SS and I have been having starting problems with it. I thought I had traced the problem to the starter solenoid and replaced it but was both disappointed and a bit demoralized when it still wouldn't start. I have a new 12 volt battery which is delivering 12+ volts so I'm comfortable that is OK. If I bypass the starter solenoid, and connect the battery positive to the starter, the engine will crank. One very basic thing that I don't understand is how this particular solenoid works. It has three terminals. Two are heavy, bolt secured terminals. The third is a smaller, flat, fin or blade type terminal. The connections are as follows: The battery positive cable and a smaller gauge red wire are both connected to one large terminal. The positive lead to the starter is connected to the other large terminal. A small gauge green wire, which I assume is the ground wire is connected to the small terminal. What I don't understand is this:It seems, from the wiring set-up I have described, that the solenoid is always being energized, which is obviously not the case, I think. I expect that the small gauge red wire somehow turns the solenoid on when I turn the key switch but I don't understand this technology. One of my partners mentioned PWM, Pulse Width Modulation, which may be involved but I'm not familiar with this. Can you explain to me how this system works. I have an understanding of how a solenoid works, but this configuration confounds me. Furthermore, if you can explain this to me, hopefully I can be on the way to getting my mower started.


#2

I

ILENGINE

The small red wire coming off the large lug of the solenoid, that is also connected to the positive from the battery, goes to the key switch to the B+ terminal. The S terminal on the key switch supplies power back to the solenoid which could go through the safety switches, and change colors someplace, terminates as the green wire that connected to the spade terminal on the starter. With the key in the start position you should have 12v at the green wire connected to the spade terminal on the solenoid. There is no separate ground for the starter, it grounds through the engine block back to the negative ground cable on the frame to the battery.

It sounds like you are not getting power to the green wire, and could be a number of things, from corroded terminal someplace, faulty key switch, faulty safety switch, bad relay some place. You may have to get out the multimeter and start checking the start circuit wiring to find the problem.


#3

Fish

Fish

Here is the diagram

Attachments





#4

J

John Ambrosia

The small red wire coming off the large lug of the solenoid, that is also connected to the positive from the battery, goes to the key switch to the B+ terminal. The S terminal on the key switch supplies power back to the solenoid which could go through the safety switches, and change colors someplace, terminates as the green wire that connected to the spade terminal on the starter. With the key in the start position you should have 12v at the green wire connected to the spade terminal on the solenoid. There is no separate ground for the starter, it grounds through the engine block back to the negative ground cable on the frame to the battery.

It sounds like you are not getting power to the green wire, and could be a number of things, from corroded terminal someplace, faulty key switch, faulty safety switch, bad relay some place. You may have to get out the multimeter and start checking the start circuit wiring to find the problem.

First of all, thank you for your amazingly quick response. Am I correct that I will need to remove the cover plate to access the key switch electronics? Once there, are the terminals you mention, B+ and S, easily recognizable? Also, I thought the green wire was a ground. I thought I followed it to the frame where it was attached to the same bolt as the battery negative/ground terminal. Am I wrong on this? Is this key switch protected by a fuse, ie. can it be something as simple as that (wishful thinking!) Lastly, I am in the market for a new multimeter, so can you recommend a brand and model to me. I don't mind spending more to get a good quality multi-use tool. Thanks again.


#5

Fish

Fish

Fluke makes the best meters out there. Basically the solenoid is just a heavy amp switch, the keyswitch sends a signal to the solenoid to tell it to connect the starter
directly to the battery. Yes, most of the Kawasakis/Skags have a couple inline fuses, find and check them first.


#6

R

Rivets

Use this procedure along with IlEngines instructions and you should be able to track down the problem. As for a multimeter, I would suggest the best one you can afford.



Electrical* problems can be very easy or very difficult, depending on four things.
1. * How well you understand basic electricity.
2. *What tools you have and know how to use.
3. *How well you follow directions.
4. *You don't overlook or assume anything and verify everything.

Remember we cannot see what you are doing. *You are our eyes, ears and fingers in solving this problem. *You must be as accurate as you can when you report back. *The two basic tools we will ask you to use are a test light and a multi-meter. *If you have an assistant when going through these tests it would be very helpful. *These steps work the best when done in order, so please don't jump around. *Now let's solve this problem.

First, check the fuse(s), check battery connections for corrosion (clean if necessary) and *voltage - above 12.5 volts should be good.*

Second, check for power from the battery to one of the large terminals on the solenoid. *One of the wires is connected directly to the battery and has power all the time so one of the large terminals should light a test light or show 12 volts on a meter at all times.*

Third, *check for power at the small terminal of the solenoid while depressing the clutch/brake pedal and holding the key in the start position (you may need an assistant to sit in the seat to override the safety switch). If your solenoid is a four wire solenoid, check both small wire terminals as one is ground and the other is power from the ignition switch. *If your solenoid is a three wire solenoid, make sure the solenoid body is not corroded where it bolts to the chassis of the mower as this is your ground path back to the battery. *If in doubt, remove the solenoid and clean the mounting area down to bare metal. *If there is no power to the small terminal then your problem is most likely a safety switch, ignition switch or in the wiring.*

Fourth, check for power on the other large terminal of the solenoid while holding the key in the start position (you may need an assistant to sit in the seat to override the safety switch). *If you have power what is the voltage?

Fifth, check for power at the starter while holding the key in the start position (assistant again). *If you have power what is the voltage?

Sixth, check your ground circuit back to the battery.

After you have gone through each of the above steps, let us know what happened when you did each step. *At that point we will have great info to tell you how to proceed. *Remember you are our eyes, ears, and fingers, so please be as accurate as possible.

Be as specific as possible with voltage readings as this will help diagnose your problem quicker. *If you do not know how to perform the above checks, just ask and I will try to guide you through it. *Youtube also has some videos and as you know a picture is worth a thousand words.


#7

Fish

Fish

On the backside of most keyswitches, the terminals are usually labeled B and S, etc...


#8

J

John Ambrosia

Here is the diagram

Thank you for the diagram. I am on the hunt for the problem. Hopefully, with your additional information, I will get there.


#9

J

John Ambrosia

Use this procedure along with IlEngines instructions and you should be able to track down the problem. As for a multimeter, I would suggest the best one you can afford.



Electrical* problems can be very easy or very difficult, depending on four things.
1. * How well you understand basic electricity.
2. *What tools you have and know how to use.
3. *How well you follow directions.
4. *You don't overlook or assume anything and verify everything.

Remember we cannot see what you are doing. *You are our eyes, ears and fingers in solving this problem. *You must be as accurate as you can when you report back. *The two basic tools we will ask you to use are a test light and a multi-meter. *If you have an assistant when going through these tests it would be very helpful. *These steps work the best when done in order, so please don't jump around. *Now let's solve this problem.

First, check the fuse(s), check battery connections for corrosion (clean if necessary) and *voltage - above 12.5 volts should be good.*

Second, check for power from the battery to one of the large terminals on the solenoid. *One of the wires is connected directly to the battery and has power all the time so one of the large terminals should light a test light or show 12 volts on a meter at all times.*

Third, *check for power at the small terminal of the solenoid while depressing the clutch/brake pedal and holding the key in the start position (you may need an assistant to sit in the seat to override the safety switch). If your solenoid is a four wire solenoid, check both small wire terminals as one is ground and the other is power from the ignition switch. *If your solenoid is a three wire solenoid, make sure the solenoid body is not corroded where it bolts to the chassis of the mower as this is your ground path back to the battery. *If in doubt, remove the solenoid and clean the mounting area down to bare metal. *If there is no power to the small terminal then your problem is most likely a safety switch, ignition switch or in the wiring.*

Fourth, check for power on the other large terminal of the solenoid while holding the key in the start position (you may need an assistant to sit in the seat to override the safety switch). *If you have power what is the voltage?

Fifth, check for power at the starter while holding the key in the start position (assistant again). *If you have power what is the voltage?

Sixth, check your ground circuit back to the battery.

After you have gone through each of the above steps, let us know what happened when you did each step. *At that point we will have great info to tell you how to proceed. *Remember you are our eyes, ears, and fingers, so please be as accurate as possible.

Be as specific as possible with voltage readings as this will help diagnose your problem quicker. *If you do not know how to perform the above checks, just ask and I will try to guide you through it. *Youtube also has some videos and as you know a picture is worth a thousand words.

Thank you for all of your time and effort. The first thing I will need to do is get a digital multimeter and test light. Then I will go through your instructions step by step and report back. Thank you again- your help is much appreciated.


#10

M

Mad Mackie

Most if not all newer Scag machines have a relay in the cranking circuit. This relay is usually located close to the key switch. When all the safety circuits are in the correct position for engine cranking, the electronic control module will ground the relay and when the key switch is in the start position, the relay will close and allow electrical power to go to the starter solenoid which in turn will close the high amperage switch internal to it and sends battery power to the starter motor.
On the Scag website on the left side is a link to manuals. You need the model and serial number and search thru to get the correct manual for your specific machine. Toward the end of the parts portion of these manuals is a section of electrical systems and then wiring diagrams.
Most of the cranking problems on these machines can be traced to the cranking relay or the seat switch.
Mad Mackie in CT


#11

J

John Ambrosia

Most if not all newer Scag machines have a relay in the cranking circuit. This relay is usually located close to the key switch. When all the safety circuits are in the correct position for engine cranking, the electronic control module will ground the relay and when the key switch is in the start position, the relay will close and allow electrical power to go to the starter solenoid which in turn will close the high amperage switch internal to it and sends battery power to the starter motor.
On the Scag website on the left side is a link to manuals. You need the model and serial number and search thru to get the correct manual for your specific machine. Toward the end of the parts portion of these manuals is a section of electrical systems and then wiring diagrams.
Most of the cranking problems on these machines can be traced to the cranking relay or the seat switch.
Mad Mackie in CT

Thank you for your time and effort. I will be getting a multimeter today and will spend the next few days trying to trace the problem. I will concentrate on the areas you mention. I will likely have further questions and need more help. Thanks again.


#12

J

John Ambrosia

Use this procedure along with IlEngines instructions and you should be able to track down the problem. As for a multimeter, I would suggest the best one you can afford.



Electrical* problems can be very easy or very difficult, depending on four things.
1. * How well you understand basic electricity.
2. *What tools you have and know how to use.
3. *How well you follow directions.
4. *You don't overlook or assume anything and verify everything.

Remember we cannot see what you are doing. *You are our eyes, ears and fingers in solving this problem. *You must be as accurate as you can when you report back. *The two basic tools we will ask you to use are a test light and a multi-meter. *If you have an assistant when going through these tests it would be very helpful. *These steps work the best when done in order, so please don't jump around. *Now let's solve this problem.

First, check the fuse(s), check battery connections for corrosion (clean if necessary) and *voltage - above 12.5 volts should be good.*

Second, check for power from the battery to one of the large terminals on the solenoid. *One of the wires is connected directly to the battery and has power all the time so one of the large terminals should light a test light or show 12 volts on a meter at all times.*

Third, *check for power at the small terminal of the solenoid while depressing the clutch/brake pedal and holding the key in the start position (you may need an assistant to sit in the seat to override the safety switch). If your solenoid is a four wire solenoid, check both small wire terminals as one is ground and the other is power from the ignition switch. *If your solenoid is a three wire solenoid, make sure the solenoid body is not corroded where it bolts to the chassis of the mower as this is your ground path back to the battery. *If in doubt, remove the solenoid and clean the mounting area down to bare metal. *If there is no power to the small terminal then your problem is most likely a safety switch, ignition switch or in the wiring.*

Fourth, check for power on the other large terminal of the solenoid while holding the key in the start position (you may need an assistant to sit in the seat to override the safety switch). *If you have power what is the voltage?

Fifth, check for power at the starter while holding the key in the start position (assistant again). *If you have power what is the voltage?

Sixth, check your ground circuit back to the battery.

After you have gone through each of the above steps, let us know what happened when you did each step. *At that point we will have great info to tell you how to proceed. *Remember you are our eyes, ears, and fingers, so please be as accurate as possible.

Be as specific as possible with voltage readings as this will help diagnose your problem quicker. *If you do not know how to perform the above checks, just ask and I will try to guide you through it. *Youtube also has some videos and as you know a picture is worth a thousand words.

I will do my best to answer your questions in the order you have raised them.

First, I have checked all three of the fuses that are shown on my wiring diagram. One is connected to the red wire to the starter and the other two are part of a harness near the key switch. All three fuses are good and intact. I am unaware of any other fuses; if there are any other fuses, please advise. Battery connections are clean. Voltage across the battery is 14v.

Second, there are 14v from the battery to the large terminal to the solenoid.

Third, there is no power at the small terminal of the solenoid with the key in the start position. Solenoid connections are clean.

Fourth, there is no power the the other large terminal on the solenoid while holding the key in the start position

Fifth, there is no power at the starter while holding the key in the start position.

Sixth, battery ground circuit is good.

Also, I have tried to test the key switch. I did not find a good wiring diagram of the key switch itself in the operator's manual, so the information I have based my testing on was obtained on line from other sources. I will describe and if I am in error please point it out and direct me otherwise. My key switch has 6 terminals. A single yellow wire is connected to one of the spade terminals. A plug is connected to the remaining 5 spade terminals. With the key in the off position, I have continuity between the G and M terminals. With the key in the lights position, I have continuity between the B and L terminals. With the key in the run position, I have continuity between the B and S terminals. I am not sure what the yellow wire is and did not include it in any of my switch testing. Should I have? If this switch testing was in error, please advise.

Also, I was unable to demonstrate continuity between the green wire at the the key switch and the green wire at the starter solenoid.

Lastly, I have tested all the safety switches I know how to test, namely the right and left handle neutral switches, the seat switch, and the brake interlock switch. I am unsure as to how to test the PTO switch, but I have a second mower and I have examined its PTO switch and the continuity pattern seems to be similar. However, I would appreciate more specific instructions as to how to accurately test it.

The green solenoid wire coming off the key switch connects to a relay and then appears to go to a module plug. Can anyone give me instructions on how to test either of these? As a last resort, I can take the relay out of my other mower and put in the bad one and see if it works, but there should be a way to outright test it.

Again, thanks to all who have contributed on this thread. I think I'm getting there and I've learned a lot along the way, and when it's not frustrating, it's fun.


#13

R

Rivets

After the tests you did we now have a starting point to solve this problem. We now we must start between step 2 and 3. I would like you to test the B terminal on the switch for 12V. If you do not have voltage, we need to find out why? If you have voltage, then you will need to have someone turn the key to thevstart position and check for voltage on the S terminal of the switch. Report back.


#14

Fish

Fish

To make things more clear, so that we are all in tune. There are usually 3 positions of a keyswitch, but your mentioned a Light position, so yours has 4 positions.

For clarity, the key turned all of the way left is off.

The key turned to the first position is in the "Run" position,

If your switch has another run{w light} position that would be next

The last position, which springs back when let go, Let us call it {crank} position'

Also, remove the switch from the plate, so you can get to the back and check for voltage with the switch plugged in.


Now, with one lead grounded to the frame, set the multimeter to dc voltage and take a reading at the B terminal on the switch, what does it read?

Now, turn the key to the run position, and take readings at the other terminals. Voltage at which terminals?

Now, with key to the "crank" position, does the "s" terminal show voltage?


#15

Fish

Fish

Parts and Diagrams for Scag STT61V-29DFI-SS Turf Tiger (C7900001-C7999999)




You can go to this link and view and magnify the wiring diagram, especially at the keyswitch, still kind of garbled, but better.


#16

Fish

Fish

Her is the diagram of the back of the keyswitch from a parts catalog.

Attachments





#17

J

John Ambrosia

After the tests you did we now have a starting point to solve this problem. We now we must start between step 2 and 3. I would like you to test the B terminal on the switch for 12V. If you do not have voltage, we need to find out why? If you have voltage, then you will need to have someone turn the key to thevstart position and check for voltage on the S terminal of the switch. Report back.

Sorry for the delay but work kept me away for a while.
1) I tested the B terminal and got 12.5 volts.
2) I tested the S terminal with the key turned and got 12.48 volts.


#18

J

John Ambrosia

To make things more clear, so that we are all in tune. There are usually 3 positions of a keyswitch, but your mentioned a Light position, so yours has 4 positions.

For clarity, the key turned all of the way left is off.

The key turned to the first position is in the "Run" position,

If your switch has another run{w light} position that would be next

The last position, which springs back when let go, Let us call it {crank} position'

Also, remove the switch from the plate, so you can get to the back and check for voltage with the switch plugged in.


Now, with one lead grounded to the frame, set the multimeter to dc voltage and take a reading at the B terminal on the switch, what does it read?

Now, turn the key to the run position, and take readings at the other terminals. Voltage at which terminals?

Now, with key to the "crank" position, does the "s" terminal show voltage?

All three positions tested regestered 12.5 volts.


#19

R

Rivets

You say you have 12V at the S terminal on the key switch. In step 3 you had 0V at the small terminal on the solenoid, when the key is in the start position. This would indicate that one of your safety switches between the key and solenoid is not closing. What you are going to do now is start at the key switch and trace the wires, checking at each connection to see where the voltage stops. When you find that you have voltage on one side of a switch, but not on the other side, jump this switch and try starting. This way you will diagnose the bad component or connection. Remember what I said in the troubleshooting procedure, DON'T ASSUME ANYTHING. Get a buddy to help you and have patience, electrical troubleshooting can get very frustrating, plus double check everything. It may take ten minutes or five hours. Post back if you need more help.


#20

exotion

exotion

This is why I don't do electrical lol


#21

R

Rivets

It's not that hard if you have patience and don't let people confuse you, by getting out of sequence. This is one time where to many cooks spoil the soup. What people don't understand is that they are not paying is product, but time and experience.


#22

exotion

exotion

It's not that hard if you have patience and don't let people confuse you, by getting out of sequence. This is one time where to many cooks spoil the soup. What people don't understand is that they are not paying is product, but time and experience.

Ya I think the patience is my downfall with electrical so far I've been fortunate and all my electrical problems have been obvious like broken wires. Seems like people just littlerly need to start at the battery follow the wires and find where the electricity stops


#23

M

Mad Mackie

The first thing that I do is find and print the wiring diagram, I then enlarge it in portions on my printer and put the sections back together.
The flow of electricity is like water in plumbing. You need to find the initial source and trace each circuit from there. No wiring diagram is totally complete, so I add in the missing items on my enlarged diagram, for example, the battery, the specific engine electrical adapter and the charging system output connection to the terminal on the keyswitch as Scag and other manufacturers don't show this for some reason. As one becomes familiar with Scag electrical systems, the function of the electronic control module becomes more evident and I make notes to these functions on the wiring diagrams.
While in the US Army, I taught aircraft maintenance as part of " additional duties assigned", I learned very soon that I had to start with basic math/algebra before going into basic electricity. And I had to drop algebra from the course title and just call it Basic Math as the word algebra was intimidating to some students. I would work in basic algebra during the course and then tell the students that they now have already been using basic algebra. Then go into basic electricity and get out the aircraft wiring diagrams, and take them out to the actual aircraft to see the actual wiring. Their confidence and skill levels would improve which was gratifying to me as an instructor.
Then we got into hydraulics and with already having math and electricity behind them, hydraulics came easily to most of them.


#24

Fish

Fish

Yeah, good advice. Pick 1 cook and stick with him......

Scags have relays and a control module that is most times the culprit, but that module is @ $100....

If the relays are all the same, swap them around and see.

Just for fun, try to get the engine to start by manually sending the voltage to the starter and solenoid, and see if the mower functions normally otherwise, check out the
safety switches that way.

The great benefit of working at a Scag dealership, is that the techs can grab a module, plug it in, and see if it cures the problem. If it doesn't, then they unplug it,
and put it back on the shelf, and try something else. But most times, it was the stupid module.... Or a relay...
If a customer buys that module, it is his, he cannot return it....


But find that cook that knows how to BBQ a big Scag..........


#25

reynoldston

reynoldston

The first thing that I do is find and print the wiring diagram, I then enlarge it in portions on my printer and put the sections back together.
The flow of electricity is like water in plumbing. You need to find the initial source and trace each circuit from there. No wiring diagram is totally complete, so I add in the missing items on my enlarged diagram, for example, the battery, the specific engine electrical adapter and the charging system output connection to the terminal on the keyswitch as Scag and other manufacturers don't show this for some reason. As one becomes familiar with Scag electrical systems, the function of the electronic control module becomes more evident and I make notes to these functions on the wiring diagrams.
While in the US Army, I taught aircraft maintenance as part of " additional duties assigned", I learned very soon that I had to start with basic math/algebra before going into basic electricity. And I had to drop algebra from the course title and just call it Basic Math as the word algebra was intimidating to some students. I would work in basic algebra during the course and then tell the students that they now have already been using basic algebra. Then go into basic electricity and get out the aircraft wiring diagrams, and take them out to the actual aircraft to see the actual wiring. Their confidence and skill levels would improve which was gratifying to me as an instructor.
Then we got into hydraulics and with already having math and electricity behind them, hydraulics came easily to most of them.

That I find that is the reason they have problems with electricity. Water only go's one way and electric has to go back to where it started to work. They are always thinking positive and not negative and without that circle it just doesn't work. Yes other then that it is a lot like water. volts flow, amps. amount of flow. A bad switch may have flow but no amps flow. Myself the electric part of it is my favorite part of working on equipment.


#26

R

Rivets

As reynoldston said electrical is fun. It can get very frustrating, but boy does that beer tastes good when you get it figured out. I can't say it too often, HAVE PATIENCE AND NEVER ASSUME ANYTHING. You'll figure it out.


#27

J

John Ambrosia

You say you have 12V at the S terminal on the key switch. In step 3 you had 0V at the small terminal on the solenoid, when the key is in the start position. This would indicate that one of your safety switches between the key and solenoid is not closing. What you are going to do now is start at the key switch and trace the wires, checking at each connection to see where the voltage stops. When you find that you have voltage on one side of a switch, but not on the other side, jump this switch and try starting. This way you will diagnose the bad component or connection. Remember what I said in the troubleshooting procedure, DON'T ASSUME ANYTHING. Get a buddy to help you and have patience, electrical troubleshooting can get very frustrating, plus double check everything. It may take ten minutes or five hours. Post back if you need more help.

The green solenoid wire goes from the key switch to a relay. I have been told these relays can fail and may be responsible for my failure to crank problem. Can you advise how to check the relay? I had tested the safety switches for continuity earlier but not for voltage and they were ok. What do you think?


#28

R

Rivets

I don't know your electrical expertise, but you need to be very careful, as you can burn up a relay quickly if you touch the wrong terminal. I shouldn't do this, assume, but I think the relay you are talking about is like the center compression relay in this attached picture. A relay is just like a solenoid, one electrical circuit controlling another. In this case the circuit between terminals 30 and 87, is controlled by the circuit between terminals 85 and 86. If you hook a continuity meter (your VOM set on Ohms) between 30 and 87, and apply 12V across terminals 85 and 86, the switch should close and you should see continuity or 0 Ohms on the meter, indicating the relay is good. If you don't have is type of relay, don't try this test. BE CAREFUL AND DON'T ATTEMPT IF YOU DON'T FEEL CONFIDENT IN DOING THIS. If you do test the relay and it is good, then you must continue to check voltage across each of the safety switches as I posted before. I know you said you checked them for continuity, but I always check to see that voltage is going through. NEVER ASSUME ANYTHING. If everything tests good, I would take the unit to your Scag dealer and ask him if he would swap out the module, as this is one electrical part that once it leaves the store 99.99% of the time is nonreturnable.


#29

Fish

Fish

After 3 pages, we recommend you take it to a Scag dealer and beg them to swap out electrical parts!!!

Sorry........ We are just a batch of bad cooks.....


#30

reynoldston

reynoldston

I have worked for enough dealers to know that they wouldn't swap out any electrical parts. They don't swap out parts in their own shop much less for a customer. What they will do, and a very good chance for free test it for you.


#31

M

Mad Mackie

The green solenoid wire goes from the key switch to a relay. I have been told these relays can fail and may be responsible for my failure to crank problem. Can you advise how to check the relay? I had tested the safety switches for continuity earlier but not for voltage and they were ok. What do you think?

Buy a new relay of the correct part number from your Scag dealer and install it. The green with black tracer coming from the relay plug goes to the electronic control module. When all the safety circuits are correctly positioned for cranking, the module will ground the relay and allow voltage from the key switch in the start position (green wire) to close the relay which in turn will operate the start solenoid and allow high amperage power to turn the starter motor.
Otherwise do as suggested and get this machine to a Scag dealer that has quality service. I'm out!!!!
Mad Mackie in CT:laughing::biggrin::smile:


#32

M

Mad Mackie

I have worked for enough dealers to know that they wouldn't swap out any electrical parts. They don't swap out parts in their own shop much less for a customer. What they will do, and a very good chance for free test it for you.

Using new parts from the parts dept as trouble shooting tools, done it many times. But there are many service departments that will keep on swapping out parts until either the item finally operates or the parts and labor bill total becomes to many $$$$$$$$$!!!
Mad Mackie in CT


#33

Fish

Fish

I thought that you were "out"!!!!



I think that we are on the same page anyway!!!

Many times there are 2 or 3 relays on a unit, and they are all the same the relay, so swapping them out would be a good idea if they are indeed the same.

I always enjoyed being on hold at the Scag tech phone lines, and these kids tried to read from a book how to test these relays and modules After sitting on the phone for a few hours, the good techs would just sneak into the parts room and grab the damn module and plug it in, and see if that was the cure......

Hell, if us chumps here could figure it out for you. we would be making big bucks......... Well, no, in this industry, we would still be making $15 an hour.........


#34

Fish

Fish

And if we or anyone else figured it out for you, you would pay us/him nothing.....


#35

Fish

Fish

Well, let us leave him with his "cook".....


#36

Fish

Fish

Sorry, I'll log out for a while......


#37

reynoldston

reynoldston

Using new parts from the parts dept as trouble shooting tools, done it many times. But there are many service departments that will keep on swapping out parts until either the item finally operates or the parts and labor bill total becomes to many $$$$$$$$$!!!
Mad Mackie in CT

Its always been a thing that wasn't done at any dealer I worked for. Not new parts. We had to test them to see if they were bad. Maybe a small dealer would do such a thing? Now how would you like to buy a new used part from a dealer not to mention a lot of new parts come in a sealed package. Now I have worked for a large company and yes we could swap parts but never at a dealer. Also I have done that, swap a relay around on the same vehicle many times because its a easy way to test them. Now working for myself I just don't have parts laying around to swap so I have to know if they are bad or good. I know you might not like this but the person that just swaps parts I will say they don't know what they are doing.


#38

M

Mad Mackie

Tell me how you test a Scag P/N 483029 electronic interlock module???
Tell me how you test a Scag P/N 483537 hour meter?
Tell me how you test a B&S P/N 797375 regulator?
Tell us that as a power equipment service technician that you have NEVER EVER used a new or serviceable part as a troubleshooting tool to diagnose a problem on a piece of equipment!!!!:laughing::laughing::laughing::laughing:


#39

J

John Ambrosia

After 3 pages, we recommend you take it to a Scag dealer and beg them to swap out electrical parts!!!

Sorry........ We are just a batch of bad cooks.....

Not a bad cook among the group!! This is a good challenge and I will get to the solution soon enough-and I am learning a ton along the way. I only wish I had more time to devote to the process all at once instead of attacking it a few minutes here and there.


#40

M

Mad Mackie

I thought that you were "out"!!!!



I think that we are on the same page anyway!!!

Many times there are 2 or 3 relays on a unit, and they are all the same the relay, so swapping them out would be a good idea if they are indeed the same.

I always enjoyed being on hold at the Scag tech phone lines, and these kids tried to read from a book how to test these relays and modules After sitting on the phone for a few hours, the good techs would just sneak into the parts room and grab the damn module and plug it in, and see if that was the cure......

Hell, if us chumps here could figure it out for you. we would be making big bucks......... Well, no, in this industry, we would still be making $15 an hour.........

Hi Fish, no doubt we are on the same page!!!
There are times when I enjoy a good retort!!!! There must be something as to why my Army co-workers named me Mad Mackie, even our Colonel picked up on it, plus a few more nick names that I won't mention here!!!!!
Later
Mad Mackie in CT:laughing::biggrin::smile:


#41

reynoldston

reynoldston

Tell me how you test a Scag P/N 483029 electronic interlock module???
Tell me how you test a Scag P/N 483537 hour meter?
Tell me how you test a B&S P/N 797375 regulator?
Tell us that as a power equipment service technician that you have NEVER EVER used a new or serviceable part as a troubleshooting tool to diagnose a problem on a piece of equipment!!!!:laughing::laughing::laughing::laughing:

I have no idea how to test any of your little list and sure not going to try. I have nothing to prove to you or anyone else what I know or don't know. I am talking about working for a dealer and going into there parts department to try parts out. Maybe that is how dealers work around by you, but no dealer I ever worked for. As I recall this all started with going to a dealer and they will swap parts to try, not going to happen with any dealer I know. As I said I have worked for a large company and we could do just what you said swap parts but that was on all their own equipment and they watched the money very close. Swapping parts is a rare option to diagnose a problem for me, I have to trouble shoot my work. Also I enjoy doing electrical work which helps.


#42

M

Mad Mackie

Hi reynoldston,
I'm a retired mech that still does selective work in my own shop, I'll do a road call now and then, but at 70 years old with a torn up right shoulder, I'm slowing down! Having been a flight engineer on military aircraft for a lot of years, knowledge of systems and the ability to diagnose their problems became my number one priority. I was part of a military aircraft ferrying crew and when I would climb aboard an unfamiliar aircraft that was supposed to be flown to anywhere in the US to include Alaska, Hawaii and Kwajalein Atoll in the Marshall Islands, (check it out, it is a long ways over the Pacific from Hawaii) every nerve in my body would start moving. I had my own tool box packages for both rotary wing and fixed wing aircraft and I would evaluate the aircraft before I inspected the paperwork. There were pilots that I refused to fly with and pilots that I would fly thru Hell's front door with and still get away. I had pilots that would only have me as a crew chief or flight engineer on ferry flights. I could and should write a book!!!
As for the little list of specific parts that I posted, they are all non serviceable items, the answer to troubleshooting them is to replace them with new after a quick but systematic troubleshooting process has been performed, which includes using a new or serviceable part in the diagnostic process.
Bear in mind that I started at 12 years old in a motorcycle, bicycle and foreign car repair shop and retired from servicing private jets a few years back, I don't know everything, but those that do, ask me for advice!!!!! HaHa!!!!!:laughing::laughing:
Smile my friend, life it too damn short!!!
Mad Mackie in CT:laughing::biggrin::smile:


#43

reynoldston

reynoldston

Hi reynoldston,
I'm a retired mech that still does selective work in my own shop, I'll do a road call now and then, but at 70 years old with a torn up right shoulder, I'm slowing down! Having been a flight engineer on military aircraft for a lot of years, knowledge of systems and the ability to diagnose their problems became my number one priority. I was part of a military aircraft ferrying crew and when I would climb aboard an unfamiliar aircraft that was supposed to be flown to anywhere in the US to include Alaska, Hawaii and Kwajalein Atoll in the Marshall Islands, (check it out, it is a long ways over the Pacific from Hawaii) every nerve in my body would start moving. I had my own tool box packages for both rotary wing and fixed wing aircraft and I would evaluate the aircraft before I inspected the paperwork. There were pilots that I refused to fly with and pilots that I would fly thru Hell's front door with and still get away. I had pilots that would only have me as a crew chief or flight engineer on ferry flights. I could and should write a book!!!
As for the little list of specific parts that I posted, they are all non serviceable items, the answer to troubleshooting them is to replace them with new after a quick but systematic troubleshooting process has been performed, which includes using a new or serviceable part in the diagnostic process.
Bear in mind that I started at 12 years old in a motorcycle, bicycle and foreign car repair shop and retired from servicing private jets a few years back, I don't know everything, but those that do, ask me for advice!!!!! HaHa!!!!!:laughing::laughing:
Smile my friend, life it too damn short!!!
Mad Mackie in CT:laughing::biggrin::smile:


I am not too far away from you in age it sounds like. Never worked on or rode in a airplane and never will. Don't like height. I started out working on sewing machines but through the many years. Just about anything mechanical from lawn mowers to dozers and a lot of thing in-between. I worked on electric fork trucks for 10 year and that is where I acquired my like for electrical work. Now back to dealers letting you go into their parts department to sample parts where you live, its not going to happen with any dealer that I know. Am I the only one that has worked for a dealer here that has a rule like that???


#44

R

Rivets

You are not the only one who can't go to the parts department to get parts to swap out, but I guess I cheat when it comes to swapping during troubleshooting. Because I taught engine repair for so long and saw so many junk units brought in for "repair", we did a lot of scraping out. If we had an electrical part that we knew was good, it got labeled and put aside. Over the years I really have too many good used parts laying around. These are the parts I use to swap out when I cannot test a component. If i found a bad component, i would remove my test component and install a new one. Only installed these components when I was giving my time and parts to someone who needed help. When I went to work at my present dealership, one of my duties was to clean up the used units for resale or scrap. Started to put together a good supply of used parts very quickly. The owner adopted this procedure and it has been working fine for the last 5 years. We still go through the normal troubleshooting procedures, but now have a faster way of getting the unit running. The other techs come to me for parts a lot, have learned that if they fail to return the part it will cost them dearly. They have even started to add to my collection. When testing electrical problems we have all burned up a new component and this procedure cuts down on the $$$ out of pocket, plus saves our customers money.


#45

M

Mad Mackie

Hi Rivets,
You and I have a lot in common!! In the 70s I worked for a power equipment/boat dealer and I had accumulated some parts for the very same purpose. The company decided to get out of the power equipment business and go with boats. When things were slow, we did a cleanup and I took 3 truck loads of good stuff over to a local tech school and some of my stash went with there too. I labeled each part for part number, condition of part and what if anything was wrong with it, they loved it!!
I have always got along with the parts folk, treat them with respect and usually you get respect in return.
I still have some of my "rat hole" aircraft parts from both military and civilian aircraft. I did send some of it to an aircraft museum that still has the last round engine aircraft that I was assigned to in the Army. On Dec 31st of 1989 the US Army stopped funding AV Gas, so all the piston engine aircraft in the Army and Guard systems died that day, it broke my heart!!! Also at that time all Army fixed wing aircraft went to contract maintenance. I was in an MOS (military occupational skill) that became extinct and I had to reclassify which was helicopter armament systems and UH-60 helicopter, was never crazy about helicopters, but I flew a lot of hours in them.
I did get to fly with the US Army Golden Knights, but I still had a "thing" about jumping out of a perfectly fine aircraft in flight!!!!:confused2:
I apologize for hijacking this thread from the original poster, but we have had some great chat, hopefully he will get his Scag Turf Tiger running!!!!
Mad Mackie in CT:laughing::biggrin::smile:


#46

reynoldston

reynoldston

You are not the only one who can't go to the parts department to get parts to swap out, but I guess I cheat when it comes to swapping during troubleshooting. Because I taught engine repair for so long and saw so many junk units brought in for "repair", we did a lot of scraping out. If we had an electrical part that we knew was good, it got labeled and put aside. Over the years I really have too many good used parts laying around. These are the parts I use to swap out when I cannot test a component. If i found a bad component, i would remove my test component and install a new one. Only installed these components when I was giving my time and parts to someone who needed help. When I went to work at my present dealership, one of my duties was to clean up the used units for resale or scrap. Started to put together a good supply of used parts very quickly. The owner adopted this procedure and it has been working fine for the last 5 years. We still go through the normal troubleshooting procedures, but now have a faster way of getting the unit running. The other techs come to me for parts a lot, have learned that if they fail to return the part it will cost them dearly. They have even started to add to my collection. When testing electrical problems we have all burned up a new component and this procedure cuts down on the $$$ out of pocket, plus saves our customers money.

Now you have gone to something different, used parts. How can I get this in your head. New parts in a sealed box. Also I am not here to argue this. Just telling you what it was like when I worked at a dealer or buy parts at a dealer. Any dealer around here won't let you bring back a electrical part once you buy it. I guess it was a lot harder for me then you because I had to learn to trouble shoot and you could just swap parts till it was fixed. That is fine by me if it works for you no skin off my A@@. The parts department and service department were two different businesses. I worked for large dealers and they would never use a used part. I also guess I never seen a dealer out to save the customer money. That is one of the big reasons I quit working for dealers over 30 years ago now and one of the better moves I made.


#47

M

Mad Mackie

Most of the small businesses that I worked for, the parts man was also the service manager, which was me at times, but I prefer to not have to deal directly with customers.
In the 70s Outboard Marine Corporation, the parent company of Johnson and Evinrude Outboard Engine companies had two strikes with union workers. Every strike was in the spring and would last for 90 days before any negotiations started as Illinois would pay strike benefits for 90 days. This would cause a serious parts and new engine problem to dealers. I think you know where I'm going with this, so no need to linger this topic.
With many parts being manufactured overseas nowadays, they are put in plastic bags to reduce the effects of corrosion as they spend a lot of time in a steel container which spends a lot of time on a ship on the ocean, many stateside manufacturers have adopted the same packaging policy.
Having worked for a local fixed base aircraft operation, when they took on a corp jet charter contract, I was tasked with setting up and stocking a separate parts department for this charter service. I bought the shelving from the shoe department of a local department store that had gone out of business. I moved all this stuff to the airport and setup and stocked this department. It took about 4 months to do this along with adding a Quick Books inventory system which was not a user friendly system. All told, the company spent 5 million dollars to set this up. Some of these parts were $50,000 plus a $20,000 core charge, just to have it on the shelf for a quick turnaround to get the aircraft back into revenue service ASAP. All aircraft parts both new and overhauled have to have paperwork even down to a #4 flat washer. The overhaul facilities must be FAA approved for specific components and their parts sources must be FAA approved, it never ends!!!
So opening up a plastic bag now and then and resealing it really is small potatoes to some of us.
Mad Mackie in CT:laughing::biggrin::smile:
Mad Mackie in CT is now OUT!!!!


#48

reynoldston

reynoldston

Small potato's trouble shooting a lawn mower with mostly on and off switches compared to a modern car, don't know anything about airplanes and don't want to learn at this age. I won't go on my house roof much less a airplane, did I tell you I don't like height. Went out west when I was younger and had to go over a mountain in my pick up truck. I was so scared that my wife had to drive us off the mountain. Just looking over a cliff my legs turn to rubber. I am so bad I can't even watch it on TV anymore.


#49

R

Rivets

Reynoldston
I guess I was not clear, when I talked about swapping parts. I would swap used parts when I got to a troubleshooting point where the component could not be tested. If I found that the used part solved the problem, would then install a new component. The only time I would leave the used part in, was when the customer was not able to afford the new part and a good will effort was more important than making money. That is only for those units which are repaired in my garage, not at a dealership. Every dealer I have worked for was in the business to make money, but not by charging the customer for parts they may not need. I call this saving the customer money, you may call it something else, but we've all done it. I think we are all on the same page here, just need a translator to understand what each of us is saying.


#50

Fish

Fish

Small potato's trouble shooting a lawn mower with mostly on and off switches compared to a modern car, don't know anything about airplanes and don't want to learn at this age. I won't go on my house roof much less a airplane, did I tell you I don't like height. Went out west when I was younger and had to go over a mountain in my pick up truck. I was so scared that my wife had to drive us off the mountain. Just looking over a cliff my legs turn to rubber. I am so bad I can't even watch it on TV anymore.

Well, you keep stepping into this thread, saying that part swappers have no idea what they are doing and shouldn't be here. Have you made 1 post that might even
slightly help the original poster and his problem?

Any help with these "small potatoes"??????


#51

Fish

Fish

I worked at a Scag dealer for a while. And as far as testing relays or that module, I originally sat on hold with the Scag techs for an hour, only to get some 24 year old kid fresh out of school, that actually has never worked on anything, going through a stupid troubleshooting chart, saying to put your test leads here, read the resistance, test here, etc, etc,,,

When you did all of that bull, he may tell you part #x is likely faulty, so replace it. If not, then try this:.............. After going through all of this bullchit, the machine still
won't crank, so you get frustrated and go grab that frigging module off of the self, plug it in, and the mower starts!!!!!!

Then your next problem is now to try and justify your wasting a hour or two on the phone somewhere so you don't get fired!!!!!! Bill the customer????


The problem with a lot of folks here is that they have no experience in the real world. A tech on the phone is not earning the dealer anything, and the dealer don't like that!!!!!

Same with warranty!!!! If the tech is on the phone for hours, no one makes money, and the dealer blames the tech!!!!!

As far as taking a commercial mower to a Scag dealer to swap out parts?????? Will not happen in any universe!!!!!

Just my take on things......


#52

Fish

Fish

Yeah, the techs at a big dealership are always on the clock to earn that big dollar!!!! The last big dealership I worked at, I got in trouble for performance/dollar amounts.

Off course I was under the gun for being the Stihl/2-cycle guy

If a customer came in with anything out of the ordinary, it seemed to fall on my bench. But when I dealt with it, it subtracted from my labor dollar earnings, since I would be on the phone with some one. An electrical problem, or a warranty problem, my bench......

And all of that time on the phone with the dist. or mfg., well, tough tittae!!!!

Those techs that can only change oil on Honda pushmowers, well they deserve t be paid better!!!!!

So sneaking into the parts dept. and fixing the damn thing quick by swapping, hell yeah!!!!!!


#53

reynoldston

reynoldston

Well, you keep stepping into this thread, saying that part swappers have no idea what they are doing and shouldn't be here. Have you made 1 post that might even
slightly help the original poster and his problem?

Any help with these "small potatoes"??????

You are right I haven't made one post to diagnose the OP problem. If you look at my pass post I don't do that anymore. The person doing the job has to diagnose their own work and as soon as I make any suggestions no one agrees or understand what I tell them. Then on top of that someone jumps in and arguers or gets mad at me. I have the feeling everyone knows much more then me so go at it. My attitude if they don't know what they are doing take it to a person that dose. All this forum is to me anymore is entertainment. I need wiring diagrams and service manuals myself or I am lost.


#54

Fish

Fish

Well, we agree there!! Which is why I always request the unit's model numbers and put up parts lists and wiring schematics if at all possible.

One goes way out on a limb to try to help folks on these forums, as the crappy info from the original poster is usually most of the problem, but one also has all of the
forum's "young guns" waiting in the wings to try to prove you wrong, because you step up and try to help. And of course, you have about 5 pissed off "old guns" that
do not like newcomers......

Either way, it is a fun ego winterfest!!!!


#55

exotion

exotion

Part swappers can be quite efficient:) I have boxes of parts from scrap. And about 50% of the mowers I buy and sell are generally fixed with spare parts. The free mowers I get if they aren't even worth fixing I take the engine off and chuck the rest makes for fast diagnosis


#56

Carscw

Carscw

I agree with all of you.


#57

J

John Ambrosia

I don't know your electrical expertise, but you need to be very careful, as you can burn up a relay quickly if you touch the wrong terminal. I shouldn't do this, assume, but I think the relay you are talking about is like the center compression relay in this attached picture. A relay is just like a solenoid, one electrical circuit controlling another. In this case the circuit between terminals 30 and 87, is controlled by the circuit between terminals 85 and 86. If you hook a continuity meter (your VOM set on Ohms) between 30 and 87, and apply 12V across terminals 85 and 86, the switch should close and you should see continuity or 0 Ohms on the meter, indicating the relay is good. If you don't have is type of relay, don't try this test. BE CAREFUL AND DON'T ATTEMPT IF YOU DON'T FEEL CONFIDENT IN DOING THIS. If you do test the relay and it is good, then you must continue to check voltage across each of the safety switches as I posted before. I know you said you checked them for continuity, but I always check to see that voltage is going through. NEVER ASSUME ANYTHING. If everything tests good, I would take the unit to your Scag dealer and ask him if he would swap out the module, as this is one electrical part that once it leaves the store 99.99% of the time is nonreturnable.

Success!!!!!! I followed the solenoid wire to the relay where it is part of a four wire wiring harness. I unplugged the harness from the relay and checked the voltage at the harness plug-12.5 volts. Next I checked the relay. I connected a 9 volt battery to the relay across the 85-86 terminals and got the tell tale click of the switch deploying. With the switch deployed, I checked for continuity across the 30-87 terminals and found I had it. However, when I checked the resistance across this interval, I got 8 ohms. I compared this to the 30-87a terminal resistance without the battery connected and this registered 0.2 ohms. So even though I had continuity across the relay with the switch activated, the high resistance was keeping it from functioning. As a final check, I pulled the relay out of my other mower and plugged it in the bad one and the mower fired right up.

Man thanks a ton for all your help and encouragement. This tread is an excellent tutorial for how to deal with trouble shooting this problem and will hopefully help others who encounter it. Yes the thread is 6 pages long but a lot of that is musings, personal opinions, and philosophy. And there's nothing wrong with that either! Well, time to buy a new relay. Thanks again-bye.


#58

M

Mad Mackie

Most if not all newer Scag machines have a relay in the cranking circuit. This relay is usually located close to the key switch. When all the safety circuits are in the correct position for engine cranking, the electronic control module will ground the relay and when the key switch is in the start position, the relay will close and allow electrical power to go to the starter solenoid which in turn will close the high amperage switch internal to it and sends battery power to the starter motor.
On the Scag website on the left side is a link to manuals. You need the model and serial number and search thru to get the correct manual for your specific machine. Toward the end of the parts portion of these manuals is a section of electrical systems and then wiring diagrams.
Most of the cranking problems on these machines can be traced to the cranking relay or the seat switch.
Mad Mackie in CT
There you go!!!!
Scag operators take note!!!!
Mad Mackie in CT
Mackie has left the building!!!


#59

R

Rivets

Glad to hear of your success, I can tell by your tone that learning to electrical troubleshoot has given you a lot of confidence. Even though it took a lot longer than you thought when you started, I'm sure your feel good that you only have to replace one part. I'll bet that beer tasted real good last night.


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