electrical weirdness (won't start, then won't stop!)

[autocol]

Hey folks,

I've got an old F1900 that has only 960 hours on it that I bought cheaply at auction sight unseen. Started it at the yards when I picked it up, drove it onto the trailer, dragged it home, and mowed about 5 acres of my place (after a quick inspection) without a drama.

At the end of that session, I turned the key off and the mower didn't stop. Eventually I disconnected the airbox hose and fully choked the air intake to stop it.

I've used it a couple of times since then, and it's been totally normal.

Now, when I turn the key, in position one the ignition light and oil pressure lights come on. In position two the glow plug light comes on. In position three (the start position)... nothing.

I've checked the park brake switch for continuity (it's good) and the PTO switch (also fine). I can't find a seat switch, if one ever existed on this machine?

I tried briefly putting 12V into the solenoid connection and it immediately kicked the starter motor, so that seems fine.

Then I turned the key again, and it started...? No idea why or how.

Then I went to turn the key off, and turning the key to the off position again does (almost) nothing. Turning it on or off does seem to actuate some kind of solenoid/lever on the throttle body, but I'm honestly not sure what that actually is (possibly a choke for improved starting?). It DOESN'T seem to be cutting off the fuel supply which is, I assume, how this engine is stopped?

I tried disconnecting the ignition switch from the loom completely at the connector (which I thought would shut down the machine) but that didn't stop it either. I resorted to choking the air intake again...

Help me, brains trust! What is likely to be wrong with this thing? Is it the ignition switch itself? I found a small fusebox with three fuses in it, all are fine. I have no idea what else to check.

Thanks for your help.

 

[autocol]

Update! Never mind folks I've figured it out.

The solenoid was the fuel shutoff solenoid, and it appears to be getting stuck in both the open and shut positions (causing both the problem of not starting AND not stopping).

I'm assuming the best fix is just going to be replacement.

 

[Diggin It]

Now, when I turn the key, in position one the ignition light and oil pressure lights come on. In position two the glow plug light comes on. In position three (the start position)... nothing.

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I tried briefly putting 12V into the solenoid connection and it immediately kicked the starter motor, so that seems fine.

Then I turned the key again, and it started...? No idea why or how.

Then I went to turn the key off, and turning the key to the off position again does (almost) nothing. Turning it on or off does seem to actuate some kind of solenoid/lever on the throttle body,

Update! Never mind folks I've figured it out.

The solenoid was the fuel shutoff solenoid, and it appears to be getting stuck in both the open and shut positions (causing both the problem of not starting AND not stopping).

How would a fuel solenoid or relay prevent the starter from cranking? Does that machine have some kind of an interlock?

Almost sounds like you have more than one issue. Maybe the ignition and one of more relays or solenoids.

 

[GreenDuramax04]

Check the wiring on that solenoid. Sometimes it looses ground and wont work. Also, there is a little fuse block under the dash. Sometimes those fuses looks continuity, just pull them out and clean the contacts.

 

[Jimbo16720]

How would a fuel solenoid or relay prevent the starter from cranking? Does that machine have some kind of an interlock?

Almost sounds like you have more than one issue. Maybe the ignition and one of more relays or solenoids.

Because the computer tells the starter not to turn. Like I said before anything with a computer is junk.