Alternator issue B&S 12.5hp riding

[mac131]

Update: I followed recommendation/help from below, cleaned alternator, tightened everything and seems to be running great again. Thanks all

Hi

I had a shop replace a motor on my 1995 Murray so the wire colors might not be correct!!! My motor was running erratically then would not start. I think the issue is my motor only had three bolts attached to the frame and was shaking and one of the wires attached to the alternator came off. One red wire which seems to have a diode on it is still attached. But another wire (I think it should be black but it is red) is just dangling. Before I notice this loose wire i could sometimes get the mower to start so I was wondering if the loose wire was grounding itself and allowing the motor to run briefly. The question is do I need to pull the fly wheel and see if I can reattach this wire to the alternator or can I ground it somewhere without pulling the fly wheel? If I don’t get an answer to this thread I’m gonna pull the fly wheel and check out the alternator and maybe replace it if I have to. I’m afraid if I try to ground the loose wire it might make all the metal parts of the mower subject to dc shock. :-(((.

 

[ILENGINE]

Lets start with the model,type,code of the engine so we can see what engine you have. 12.5 hp covers over 1000 models.

 

[mac131]

Lets start with the model,type,code of the engine so we can see what engine you have. 12.5 hp covers over 1000 models.

Well I found a engine manual based off the model and when I took off the flywheel and I have what appears to be a DC Only alternator which has only one red wire as it is a half circle. I’ve attached a pic of the model etc. it’s a 12hp. Now I’m looking for a wire diagram to see where this other wire goes. Maybe it just needs to be grounded??

 

[mac131]

I am also attaching a pic of the wire. The red wire resting on the starter is thd broken one. Don’t see any place it has detached from.

 

[ILENGINE]

My guess is that red wire could of been for headlights.

 

[Scrubcadet10]

Here are some alternator guides,. though it looks like you've got it now.

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[mac131]

My guess is that red wire could of been for headlights.

The headlights worked with this wired detached so not sure. I’m going to put it back together as it seems this wire is not related to the alternator. Thanks for your comments.

 

[StarTech]

Someone has replaced the engine with a single wire stator and failed the remove the unnecessary wiring. Just remove the loose wire. Originally your mower had a dual circuit stator.

Personally this is shoddy workmanship by a fly by night shop.

 

[mac131]

I feel like this detached wire is causing my engine to not get spark so I feel it needs to be grounded.

 

[StarTech]

That is the remains of the dual circuit stator. The red originally provide DC from the stator and was never grounded. The black was the AC for the lights. The system has been rewired to provide 12 VDC to the lights now.

Also your engine has a magneto type ignition coil that is grounded to kill the spark not to cause spark. Some floks even apply 12v to the kill terminal destroying the magneto coil electronics.

Remove the engine shroud and disconnect the kill wire on the coil then check for spark. IF you get spark then somewhere the coil's kill wire is being grounded; otherwise, you have a bad ignition coil.

IF you would the model number of the Murray we might find the original wiring schematics.