Helping an old friend and his 125

[TommmR]

I'm new to the forum, but only because I'm helping an old friend with his 125. After rewiring his burnt up harness, and doing a maintenance once-over(plug and wire, oil change, grease), the starter turns very weakly. I've gone through the faqs, cleaned all connections, checked voltage drop at each stage, and cranked w/two car batteries in parallel. Still slow cranking and 11.5 v at the starter. I've even jumped the battery directly to the starter.

I've opened the starter/gen, cleaned and undercut the commutator, checked the bearing/bushing(OK), and cleaned the post connections. I've checked continuity on the rotor. The brushes look ok, but the owner says he had it rebuilt last summer by an automotive alternator/starter shop.

Any ideas why it turns over slowly? I get about 6 slow revolutions, and the motor pops each time but not enough to kick it to life. Is it possible the wrong brush material(automotive vs tractor) could cause weak cranking?

Thank you-
Tom

[IACubCadet]

I would try another starter/generator if you may have one. This would help you eliminate possible bad grounds (even though you checked them). Make sure you have good cables for ground and the soleniod as well.

[CADplans]

It may be mechanical rather than electrical!!

There is an automatic (centrifugal) compression release that makes the engine spin faster.

[zippy1]

Check out, "starter problems" in this forum.

[TommmR]

Thanks for the replies. I've cleaned the ground connections, and even tried a separate cable from the ground post to the starter/gen. I'll check into the compression release after that. Maybe I'll try jumping the start interlock and release the brake, in case the fwd/rev lever is not properly centered and is dragging the motor down.

Unfortunately I don't have a spare starter.

[Methos]

Sounds like your heading in the right direction! I hope you get it figured out soon!

[ACecil]

Originally Posted by Methos

Sounds like your heading in the right direction! I hope you get it figured out soon!

Same here.

[TommmR]

I checked the valve clearances just in case they might be affecting my issue, and they were in range.
Does anyone in the NE CT area have a starter/gen that I could try out, to verify whether or not it's the starter?

I don't want to spring for another one if the problem lies elsewhere.

Thanks

Tom

[Sugarmaker]

Tom,
Do you have a starter generator repair shop in the area? We have a good shop that rebuilt My S/G in about 4 hours after I toasted it! And it saved me a lot of dollars too!
Regards,
Chris

[TommmR]

Good idea; I just dropped the starter off at Woodstock Rebuilders- fingers crossed!