Kubota B7800 Fuel Solenoid

[Miket1961]

A poster above sez it has to ground thru the valve body....if so....why would there be a ground wire ???
Just trying to help out.

Overlooked that, thanks. I've been going around in circles trying to find the correct wiring that I'm confusing myself.

 

[thepumpguysc]

Blondie.. IDK.. but it does.. I had a new one in my hand once & was trying to diagnose a "no start" condition..
I had "jumpers" hooked up & it wouldn't pull in.. I "thought" it was bad..
I laid it down on the engine to grab a tool & it "snapped in".. WTH??
So I picked it up & the plunger shot out again.. I grounded it on the pump & sure enough it snapped in again..
So I don't know why.. it just does..

 

[Miket1961]

Blondie.. IDK.. but it does.. I had a new one in my hand once & was trying to diagnose a "no start" condition..
I had "jumpers" hooked up & it wouldn't pull in.. I "thought" it was bad..
I laid it down on the engine to grab a tool & it "snapped in".. WTH??
So I picked it up & the plunger shot out again.. I grounded it on the pump & sure enough it snapped in again..
So I don't know why.. it just does..

There a two wires going to this solenoid. I assumed that one was a hot wire and one was a ground. Could it be that one picks up to start and the other is a run coil and the coil grounds through its case to the fuel block. Thanks

 

[orezok]

Heres the wiring diagram for B7800 solenoid.

 

[Miket1961]

Heres the wiring diagram for B7800 solenoid.

View attachment 585843

Thanks so much !!

 

[7Jetboy]

Hello, I'm helping a friend troubleshoot an intermediate problem with his fuel solenoid. It seems to arbitrarily de-energize. We took the dash apart and jiggled wires on the dash and near where they go under the fuel tank. We were unable to find anything definitive. When the solenoid was energized I checked the wire(rd/bk) wire from the key switch to the hot wire on the solenoid and put in a jumper wire from right at the switch to the the plug on the solenoid as a means to troubleshoot . The tractor still stalled out within 15 minutes or so of operating it. I'm having a hard time finding a wiring diagram so that I can properly troubleshoot it. I'd really appreciate any help with this and more so information about the wiring for this circuit.

I was going through the same thing with my B7800! It would start then just quit. When I tried to restart, the engine would turn over but not start. The stop solenoid was not engaging which you'll hear when turning the key - it clicks and is very audible. The tractor would work fine for a while then it would act up. If I left the tractor for a few minutes and came back to it, it would start and run fine at times. Then it would run and turn off arbitrarily and I'd have to wait for the stop solenoid to engage so I could restart the engine. After changing a few parts, I got behind the dash of the tractor. There was a mouse nest in there and I cleaned that out. Fortunately, there was no wire damage. I checked everything behind the dash, changed the relay, still did not fix the issue. Then, with the key turned to the run position, I jiggled the controller (it's behind the fuel gauge) and the stop solenoid engaged (clicked) and the tractor would start. So, I purchased and replaced the controller ($155) and the issue has been fixed!! Been running without issue since then!

 

[Kingston1960]

I was going through the same thing with my B7800! It would start then just quit. When I tried to restart, the engine would turn over but not start. The stop solenoid was not engaging which you'll hear when turning the key - it clicks and is very audible. The tractor would work fine for a while then it would act up. If I left the tractor for a few minutes and came back to it, it would start and run fine at times. Then it would run and turn off arbitrarily and I'd have to wait for the stop solenoid to engage so I could restart the engine. After changing a few parts, I got behind the dash of the tractor. There was a mouse nest in there and I cleaned that out. Fortunately, there was no wire damage. I checked everything behind the dash, changed the relay, still did not fix the issue. Then, with the key turned to the run position, I jiggled the controller (it's behind the fuel gauge) and the stop solenoid engaged (clicked) and the tractor would start. So, I purchased and replaced the controller ($155) and the issue has been fixed!! Been running without issue since then!

Thank you 7Jetboy
Your Information was very helpful

 

[Henro]

Thank you 7Jetboy
Your Information was very helpful

I believe I read somewhere that the later produced models of the B2910 and B7800 use a different electrical setup with an OPC (operator presence control) module that controls the fuel cutoff solenoid. This caught my attention as I have a B2910.

If my memory is telling the truth, one needs to make sure which version he has when troubleshooting electrical problems.

Mine does not have the OPC module fortunately. It is a small plastic box under the dash somewhere, with a number of wires going into it. I want to think if the tractor has a seat presence switch this may indicate it’s a model that has the OPC unit.