F3060 only runs when key is in the crank position

[sab]

I have an F3060 that only will run when the key is in the cranking position. Once the key is released, it stops. Occasionally, it will actually start and then continue running, only to die while mowing. I realize as a diesel engine, the only way to stop it is to shut off the fuel flow, so there is clearly something in the fuel cut off solenoid circuit. I've replaced the solenoid twice, and it seems to work for a while and then it goes back to this behavior. For a test, I wired a toggle switch to the soleniod so that i can manually control wether it is on or off, and then the tractor runs fine. But I hate to have this kind of a hack job going on a piece of equipment.

Looking at the wiring diagram everything seems to go into the "combi box" and i'm wondering where that is located, and if anyone thinks there may be a problem with it.

I'd also like to know if anyone has the ignition switch wiring, the diagram I have is to small to make out much, there are 4 wires on the switch. Red Red/White Black/Red Black/White. And the odd thing is that the Red/White wire has continuity to the battery ground, but as far as I can tell, its always hot (12v) so I don't think that this is a problem.

Any suggestions would be appreciated.

 

[Tooljunkie]

From your description the combi box is the issue. You seem to present you have some knowledge of the basic operation for the fuel cut off solenoid. Two circuits in solenoid, start and run. Actually on solenoid is pull and hold. During crank it pulls and in run position the other wire holds it. My take on the situation would be the combi box cant take the load.so either solenoid is wired backwards and its damaging combi box due to load on wrong circuit or replacement parts arent as good as we would like.
My work around would be adding a couple relays and fuses to carry the load, then combi box is just a trigger.

 

[OrangeMopar]

Have you checked the ignition switch for proper continuity? I recently had a similar problem with my Toro Groundsmaster. I had random no start and sometimes could not shut it off by the key. Turned out the switch was getting resistance on some of the terminals. $15 replacement on Ebay fixed it. Something to check.

Sent from my LGL41C using Tapatalk

 

[sab]

Thanks for the reply. I've got a few additional questions about this.
On the solenoid, the "pigtail" has 3 wires, Red, Black, White. Obviously the Black is ground (verifed it with the connector on the tractor that plugs into the pigtail). Do you know which wire is the hold, and which wire is the pull and which is the hold (i guess it does not really matter if I put relays on both circuits, which I can do easily enough, since I've already split the on tractor connection with a weather pak connector (made it easier to wire up my switch hack). I guess its off to autozone this weekend to get a couple of relays).

Re the ignition switch. It all seems good from an electrical perspective. I've got continuity on all the different positions when I tested it on the bench.

 

[sab]

Thanks to all. The issue is that there is no voltage on the hold coil circuit, which means (naturally) that the solenoid is only energized by the pull circuit when cranking. I just put a switch to a relay on that circuit and used the mower for 2 hours without any hicups (i put a rely on the pull circuit as well, no reason not to, but in this case it is not really necessary).