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fuses getting hot

#1

J

jt2shot

my mower is getting the fuses hot they don't blow but they melt the plastic !! the mower run good for a while and then it cuts to half power. I have replaced the regualtor and the clutch this year , the mower has about 1540 hrs on it. my mower is a scag turf tiger 61 in with a kohler 25 hp. NEED HELP BAD!!! a friend said maybe a relay? what do you think?:confused2:


#2

EngineMan

EngineMan

I would renew the fuse holder if the fuse's are not blowing, its pulling Amps so maybe the contacts are not that tight so getting hot, and as you say melting the plastic.


#3

J

jt2shot

I just check the relay took one off my buddys mower and it still does the same. and we check the fuses and the holder fuses are tight even hard to get out one might say.
:confused2:


#4

EngineMan

EngineMan

And what about the connections to and from the fuse holder.


#5

J

jt2shot

ok I just found out that the seat switch does not shut off the mower when you get off. but it still works for the start up. you have to be on before it will start. but you can dismount while mower and blades are on. not safe but what controls that . the seat switch checks out with tester.


#6

EngineMan

EngineMan

This may help you out.

Attachments





#7

J

jt2shot

Thanks I just found that the coil pack on the right side is dead. I guess it worked until it got hot. would this make the fuse get hot??????


#8

R

Rivets

I would be looking for a wire that has a crack in the insulation causing and intermittent short. Second what size fuses are in there? They may be too big for the system and don't blow. Third is it one or both fuses? Finally, do you have the ammeter? If so what is it reading?


#9

EngineMan

EngineMan

I would have thought so if it was shorten. replace coil and you will soon know...!


#10

EngineMan

EngineMan

Welcome back Rivets, are you thinking that the gen is giving out too many amps...!


#11

R

Rivets

Could be or it is spiking intermittently. If he has the ammeter he could see bounce a high speeds. My guess is a component short or wire rubbing. These will also show up on the ammeter if he watches closely.


#12

M

Mad Mackie

Get the serial number of your machine, go to the Scag website, click on manuals on the left, click on STT, find your serial number group, click on the parts manual. It will download as a pdf and toward the end of the manual are the wiring diagrams, print out the one that has your engine.
Generally when fuses get hot there are several causes; the voltage regulator in the regulator/rectifier is letting the voltage get to high. With the engine running at half throttle or more, the voltage across the battery should be not more than 14.3 VDC. All battery power passes thru the key switch and several connectors along the way, all of which are subject to high resistance from corrosion and dirt. The charging system output is also controlled by the keyswitch and when in the off position, the charging system is isolated so battery power won't back feed and drain the battery. Keyswitches are known to go bad. As has been mentioned, chaffing of wiring is always a possibility. Battery ground connections which are generally connected to an engine mounting bolt are another possible problem source. Why did you install a new clutch? Have you needed to recharge the battery between machine uses?


#13

F

FGMC

On my Scag Wildcat the PTO clutch was worn to the point it needed adjustment. The fuses blew more often in thicker grass. I noticed the wiring to the fuse holder was also getting hot and even had to replace PTO switch. Maybe this will help..........


#14

B

Black Byrdz

FGMC said:
On my Scag Wildcat the PTO clutch was worn to the point it needed adjustment. The fuses blew more often in thicker grass. I noticed the wiring to the fuse holder was also getting hot and even had to replace PTO switch. Maybe this will help..........
Click to expand...

What was the final answer to the ( fuses getting hot)? PTO Swich, Key switch ,bare wire, coil pack?????????? My scag Turf Tiger is doing the same thing.
.


#15

M

Mad Mackie

Unfortunately, most that post on this forum with a problem never get back to the group with what resolved their problem. I have a few adjectives in mind, but I'm not going any further on this subject!
So, if you post a problem and the problem gets resolved from any source, please have the consideration to respond to the folks on this forum with what resolved the problem. After all, communication is a two way deal and that is what these forums are all about!!
Just my thoughts!!
Mad Mackie in CT:laughing::biggrin::smile:


#16

R

rabbit

Mad Mackie said:
Get the serial number of your machine, go to the Scag website, click on manuals on the left, click on STT, find your serial number group, click on the parts manual. It will download as a pdf and toward the end of the manual are the wiring diagrams, print out the one that has your engine.
Generally when fuses get hot there are several causes; the voltage regulator in the regulator/rectifier is letting the voltage get to high. With the engine running at half throttle or more, the voltage across the battery should be not more than 14.3 VDC. All battery power passes thru the key switch and several connectors along the way, all of which are subject to high resistance from corrosion and dirt. The charging system output is also controlled by the keyswitch and when in the off position, the charging system is isolated so battery power won't back feed and drain the battery. Keyswitches are known to go bad. As has been mentioned, chaffing of wiring is always a possibility. Battery ground connections which are generally connected to an engine mounting bolt are another possible problem source. Why did you install a new clutch? Have you needed to recharge the battery between machine uses?
Click to expand...

Thanks "Mad". I am having the same problem as the original post. this advise you have given will certainly help me get started with trouble shooting.

My machine has 20amp and 30amp fuses. 30 was on the pto clutch relay. [scag turf tiger 52 ", 25 kohler command].
holders get hot and then fuses lose contact.

I'll go thru your check list in a couple days.

randy


#17

M

Mad Mackie

Check your manual as I don't know of any Scag machines that use a 30 AMP fuse, just 20s. You may need a new clutch as when there are electrical problems in the electromagnetic coil then amperage draw increases to the point where the charging system cannot meet the demand from the clutch.


#18

R

rabbit

Mad Mackie said:
Check your manual as I don't know of any Scag machines that use a 30 AMP fuse, just 20s. You may need a new clutch as when there are electrical problems in the electromagnetic coil then amperage draw increases to the point where the charging system cannot meet the demand from the clutch.
Click to expand...

Mr. Mad, Do you know of any way to check the clutch for high amp draw or do you suggest go and buy a new clutch and hope that is the fix?

thanks, randy


#19

M

Mad Mackie

Check out this attachment. The resistance in the clutch coil will tell you if it is out of spec. The lower the resistance, the higher the amperage draw. You more than likely have an Ogura clutch. Find the power plug for the clutch, disconnect it but be careful as it has a lock tab on it that must be lifted up a little to unlock it. Then you can check the resistance of the clutch coil.

Attachments


  • Ogura GT3.5 electricclutchadjustment.pdf
    57 KB · Views: 48


#20

R

rabbit

Mad Mackie said:
Check out this attachment. The resistance in the clutch coil will tell you if it is out of spec. The lower the resistance, the higher the amperage draw. You more than likely have an Ogura clutch. Find the power plug for the clutch, disconnect it but be careful as it has a lock tab on it that must be lifted up a little to unlock it. Then you can check the resistance of the clutch coil.
Click to expand...


thanks I will let you know in a couple days my results.

randy


#21

R

rabbit

Mr. Mad, just downloaded and printed the owners operator manual. My machine falls into the 4320026 category.

The parts section only refers to the clutch as a clutch with out a manufacturer name.

The clutch does indicate with a sticker " Warner Electric Mag Stop".

the Voltage Out put checked at the battery at full throttle - 13.8

I still need to check the other things mentioned.


Battery Ground connect- need to inspect

Also the amp meter does not indicate it is doing or showing anything. Could that mean something?

thanks, randy


#22

M

Mad Mackie

Check the clutch for internal resistance per the attachment in a previous thread, do this first!
Look at the wiring diagram, near the top to the left of the figure that is engine is a red/yel wire, this is connected to the battery positive (red cable) terminal on the started motor. Trace this line and you will see that it goes to the fuse with the red wire, to the ammeter positive terminal, out the ammeter negative terminal, to the key switch. The red wires on the key switch are power out when the switch is in the on position. One red wire goes to the module, the other goes to the PTO switch and when the PTO switch is in the on position, then out the blue wire to the clutch. note that the black wire in the clutch plug goes to ground. The electronic control module is the safety circuit control center for all machine operations.
The parts manual calls for a Scag P/N 461716 which is an Ogura GT 3.5 series clutch. This is an upgrade from the Warner clutch currently on your machine. It is a kit which contains all necessary parts to make the change to the Ogura clutch.
As for ammeters, if yours is not indicating anything I suggest that you replace it. Key switches are known to go bad and it is the second item in the power supply to your machine. The yel wire in the diagram next to the key switch is the charging system output. It actually connects to another terminal on the key switch and when the switch is in the on position the circuit is completed to send the charging system output back into the system to charge the battery and power all electrical components while the machine is operating. When the key switch is in the off position, the charging system is isolated from the electrical system to prevent back feed which will discharge the battery when the engine is not running.
Mad Mackie in CT


#23

M

Mad Mackie

My Tiger Cub has an Ogura GT 3.5 clutch. With the engine running at full RPM, battery voltage is 14.2 VDC, when pull the PTO switch on, the voltage drops to and remains at 13.8 VDC. This is with a fully charged battery in good condition and a correctly operating charging system.


#24

R

rabbit

thank you Sir. I will be back in touch. Currently have some distractions keeping from trouble shooting my gremlin!

randy


Mad Mackie said:
Check the clutch for internal resistance per the attachment in a previous thread, do this first!
Look at the wiring diagram, near the top to the left of the figure that is engine is a red/yel wire, this is connected to the battery positive (red cable) terminal on the started motor. Trace this line and you will see that it goes to the fuse with the red wire, to the ammeter positive terminal, out the ammeter negative terminal, to the key switch. The red wires on the key switch are power out when the switch is in the on position. One red wire goes to the module, the other goes to the PTO switch and when the PTO switch is in the on position, then out the blue wire to the clutch. note that the black wire in the clutch plug goes to ground. The electronic control module is the safety circuit control center for all machine operations.
The parts manual calls for a Scag P/N 461716 which is an Ogura GT 3.5 series clutch. This is an upgrade from the Warner clutch currently on your machine. It is a kit which contains all necessary parts to make the change to the Ogura clutch.
As for ammeters, if yours is not indicating anything I suggest that you replace it. Key switches are known to go bad and it is the second item in the power supply to your machine. The yel wire in the diagram next to the key switch is the charging system output. It actually connects to another terminal on the key switch and when the switch is in the on position the circuit is completed to send the charging system output back into the system to charge the battery and power all electrical components while the machine is operating. When the key switch is in the off position, the charging system is isolated from the electrical system to prevent back feed which will discharge the battery when the engine is not running.
Mad Mackie in CT
Click to expand...


#25

R

rabbit

Mr. Mad, Not that I have for gotten your recommendations but I went ahead and change the fuse holders and put the appropriate 20 amp fuses in.

The holders were warped and bad anyway.

Now things seem to be ok!

Fuse holders not getting hot.

The amp meter is still not working so I will change that.

Could my gremlin problem be solved? Probably not. I am still going to trouble shoot as you suggest.

thanks randy


#26

R

rabbit

I did all the troubleshooting suggested. I can not find the cause of the fuse holders getting hot. I did change them and now all seems to be ok.

Fuse holders are not getting hot now.

Maybe that was the problem, they were wore out [if that is possible].

Thanks for all your help. If problem reoccurs and I find the solution I will let you know.


#27

M

Mad Mackie

I have had fuse holders fatigue and loose their normal grip on the blades of the fuse.
I recommend that you check the system voltage at the battery with the engine at full throttle as a malfunctioning voltage regulator can cause excessively high voltage in the system which also can cause overheat in the fuses.
System voltage should be 14.1-14.3 VDC when stabilized at full throttle.
Mad Mackie in CT


#28

R

rabbit

Mad Mackie said:
I have had fuse holders fatigue and loose their normal grip on the blades of the fuse.
I recommend that you check the system voltage at the battery with the engine at full throttle as a malfunctioning voltage regulator can cause excessively high voltage in the system which also can cause overheat in the fuses.
System voltage should be 14.1-14.3 VDC when stabilized at full throttle.
Mad Mackie in CT
Click to expand...


full throttle 12.99vdc, blades engaged- 13.23 vdc


#29

M

Mad Mackie

rabbit said:
full throttle 12.99vdc, blades engaged- 13.23 vdc
Click to expand...

I hope that you meant 13.99 VDC, blades engaged 13.23 VDC!!
My Tiger Cub does 14.12 VDC at full throttle and 13.8 VDC when the blades are engaged and my clutch is out of spec.
I just stopped at my local Scag dealer and they are out of stock in my P/N clutch. They will get more in on Wednesday. My clutch should have between 2.8-3.2 Ohms in the coil when cold, but it is now down to 2.3 Ohms which increases the amperage demand of the charging system and approaching it's maximum capacity output.
Mad Mackie in CT


#30

R

rabbit

Mad Mackie said:
I hope that you meant 13.99 VDC, blades engaged 13.23 VDC!!
My Tiger Cub does 14.12 VDC at full throttle and 13.8 VDC when the blades are engaged and my clutch is out of spec.
I just stopped at my local Scag dealer and they are out of stock in my P/N clutch. They will get more in on Wednesday. My clutch should have between 2.8-3.2 Ohms in the coil when cold, but it is now down to 2.3 Ohms which increases the amperage demand of the charging system and approaching it's maximum capacity output.
Mad Mackie in CT
Click to expand...


I just checked it again, 13.06 vdc at at full throttle, 13.23 blades engaged.


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