John Deere STX38 electrical problem??

[goosemasterkl]

A friend of mine has a John Deere TX 38 w/yellow deck 12.5hp Kohler engine and here is the problem he's having. When he went to mow his yard he had to jump it to start it. While mowing it quits and he had to jump it again; mows somemore and quits again. He takes it to be fixed and they put a different starter,flywheel,charging system, and pto switch on it. He takes it home and starts mowing and it dies again. He jumps it and then after mowing somemore it dies again. So he goes and buys a new battery and gets it running and finishes his mowing. Today he goes to start the mower to mow again and he has to jump it to start it. And while he's mowing it dies on him so he takes the battery out and takes it where he bought it and they said it was good and showing 100%. Can anyone please give me some advice on what we can do to find the problem on his mower? Thanks in advance to anybody who replies. The mower model# is MOOSTXB037303

 

[StarTech]

Sounds like the shop used the kitchen sink approach.

To me it sounds like a partial shorted PTO clutch that is over taxing the charging system. I have seen clutches to pull over 15 amps and still operate. Using an ohm measure the PTO clutch coil to see if the resistance is 1.7 ohms or higher. IF below 1.7 ohms it needs replacing. Normally these clutches pulls 3-5 amps with 7 amps being the max. This is why I fuse these clutches with a 7.5 amp fuse. If that fuse blows that I know sure there a PTO clutch problem. Also note sometimes the resistance is fine but the bearings are shot and the clutch is shorting out while operating. Kinda rare as usually it is the coil (field windings) that is the problem. I think in the 15 yrs I have seen only two that was shorting out during operation.

 

[goosemasterkl]

Sounds like the shop used the kitchen sink approach.

To me it sounds like a partial shorted PTO clutch that is over taxing the charging system. I have seen clutches to pull over 15 amps and still operate. Using an ohm measure the PTO clutch coil to see if the resistance is 1.7 ohms or higher. IF below 1.7 ohms it needs replacing. Normally these clutches pulls 3-5 amps with 7 amps being the max. This is why I fuse these clutches with a 7.5 amp fuse. If that fuse blows that I know sure there a PTO clutch problem. Also note sometimes the resistance is fine but the bearings are shot and the clutch is shorting out while operating. Kinda rare as usually it is the coil (field windings) that is the problem. I think in the 15 yrs I have seen only two that was shorting out during operation.

Do I check the ohm's resistance at the pto clutches electrical plug? Thanks for your reply. I was thinking along the lines of the clutch because I had him to see if the flywheel was hard to turn with his hands. I've fixed 2 clutches this year that was freezing up .on the engine shaft

 

[StarTech]

Yes.

 

[bertsmobile1]

Quick & dirty test is to slip a 5A fuse where the usual 7,5A one is
If it blows then you most likely have a bad clutch
Also check the clutch wires it is not uncommon for them to chaff and create a short
Finally try running with the alternator unplugged
Let us know how you go .

 

[Tiger Small Engine]

Sounds like the shop used the kitchen sink approach.

To me it sounds like a partial shorted PTO clutch that is over taxing the charging system. I have seen clutches to pull over 15 amps and still operate. Using an ohm measure the PTO clutch coil to see if the resistance is 1.7 ohms or higher. IF below 1.7 ohms it needs replacing. Normally these clutches pulls 3-5 amps with 7 amps being the max. This is why I fuse these clutches with a 7.5 amp fuse. If that fuse blows that I know sure there a PTO clutch problem. Also note sometimes the resistance is fine but the bearings are shot and the clutch is shorting out while operating. Kinda rare as usually it is the coil (field windings) that is the problem. I think in the 15 yrs I have seen only two that was shorting out during operation.

2-4 ohms is the normal acceptable range for most PTO clutches. I have replaced 3 PTO clutches so far this year.