confirming that a bad starter is my problem...

[gbonawitz]

Hi. I have a Super LT1500 that won't start.

For the longest time sometimes when I'd try to start it I'd hear a ~ thunk but nothing more; then I'd have to turn the key off and then try again and it'd start. (I'm wondering if that sound was the starter pinion engaging the flywheel but not turning it.)

Now I'm at the point where when I turn the key I don't even hear the "thunk".

I did try a benchtop test of the solenoid after removing it, and it seems to work correctly.

I also removed the starter and did a benchtop test, and it seems to work fine by itself.

One odd thing I noticed: with everything hooked up in the tractor I took a voltmeter to the post on the starter + chassis ground, and when I turn the key I see only 4-5 volts. If I disconnect the red wire going to the starter post and measure it's voltage I see 12 volts when I turn the key.

I did bypass my tractor batter and hooked up my car's battery and see the same behavior 4-5 V and 12 V behavior... so I think that eliminates the tractor battery as the culprot (and my battery charger states the tractor battery is at 90%).


- Benchtop-wise both the solenoid and starter seem to work by themselves.
- Regardless of tractor or car battery I see that weird 4-5 V versus 12 V behavior

I'm guessing maybe its still something with the starter, i.e. a short... but that doesn't seem to match up with the fact that on the benchtop the starter works/spins.

Last clue (maybe): I took the starter apart and measured the continuity on the commutator. I get continuity from any one terminal around the circumference to every other terminal on the circumference - shouldn't that continuity only be in pairs?

Thanks for any suggestions.