Testing solenoid/starting circuit???

[dpb]

OK, I'm stumped...

JD 112H lawn tractor (nearly ancient)

Symptom is no voltage in ignition system when turn key to "on/start".

Have had issue on occasion w/ safety interlock on tranny, but that ain't the problem this time; have tested continuity from switch connection thru both safety contacts (transmission and blade) to connection at solenoid and is good. Plus, when one of them fails to make contact, won't crank but does get voltage to generator charge light; not getting that far now.

Question -- is way to test if solenoid isn't operating might be issue? Service manuals aren't online but here's a link to the parts diagram for the wiring harness that is a fairly complete wiring layout.

I scanned the wiring diagram I have; don't know how good it'll be but there's a copy posted here...

Any troubleshooting help/suggestions appreciated...

[Hustlin' Hank]

Knowing the engine type and model would help. Anyway, you should have one wire coming from the magneto. This is nothing more than a kill switch. Disconnect it. After disconnecting it, make sure it isn't touching any metal. Then jump the solenoids 2 big wire lugs. This will make the engine turn over and start (assuming there isn't other issues). BUT! in order to stop it, you must ground that wire to the engine/frame.

Hank

[Hustlin' Hank]

I forgot to add...............if it starts after doing what I said, you either have a bad ignition switch, bad solenoid, or a wiring/fuse issue. I can't tell you which unless I know what kind of solenoid you, then I could tell you how to test the solenoid.

Hank

Hank

[dpb]

Hustlin' Hank wrote: ...

Tecumseh HH100

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[dpb]

Well, what a combination of coincidental stuff, particularly as happened since last used at which time had no problems!!!

First off, rebuilt tranny early this spring and while had it apart took the opportunity to clean up longterm effects of battery spills. Apparently did not get the nut holding the jumper from the battery side of the solenoid to the 'bat' terminal on the regulator tight so the apparently the nut came off while it was running the last time and simply contacting the stud kept it running while it was. When changed out the battery (the old one had gotten to where it was no longer holding charge) apparently I knocked it off completely--hence the "no voltage" symptom. Given the location deep down under the battery cage and fuel tank, it wasn't simple to see so missed it wasn't connected early on. Anyway, one would think that replacing that would fix all, wouldn't one? Well, .... :(

Did get ignition light, no kick. Back track, discover bad connection at switch isn't making contact all the time. Clean contacts, test, all's well.

Put all back together (had to take tank, battery holder, etc., off to get to switch contacts to check and clean them) and poof!!! no kick again.

Now, trace back to another dirty contact in the safety circuit that while pulling on the wiring harness to fix the switch contacts caused to now show up...

Pull apart again to get to it; retest...bingo!

This time, _FINALLY_ it cranks and runs...

Anyway, thanks for the input...

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[Tony Hwang]

Hi, Sudden death is easy to fix. Remember IBM motto? Think(logic)! After thought. You did not mention tranny rebuilding after all!

[dpb]

Tony Hwang wrote: ...

POAD... :(

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