B7800 Fuel Stop Solenoid

[Bill Martin]

Reading several threads on other Kubota models on this subject I've gained some info. But need more help. Here's my dilemma.

2nd hand tractor running great, I've had it a few months (less than 100 hours), less than 500 hours total on this 2005 model. Couple weeks ago it just died. I smelled an odd smell (something overheating?) just before the engine stopped. Blew out the solenoid fuse. Isolated problem to the fuel stop solenoid. Bought new part ($149) and replaced.

Tractor starts beautifully BUT the new solenoid heats up very quickly. I mean in one minute it's too hot to touch. On first try the engine shut down when, I suppose, a resister stopped the damage. But no fuses blew. Let it cool but on the second try I didn't let it overheat. Once cool, the solenoid clicks when the key is turned. Engine starts beautifully. But, again, the solenoid gets SUPER hot. I shut it down and haven't started again, and won't, until I diagnose the issue.

Has anyone had a similar problem? Could it be a bad timer or relay or some switch that is letting the solenoid overwork? If so, can anyone walk me through how to make the fix? Thanks in advance. Bill

 

[art]

They normally do get warm. I can't visualise super hot but you should be able to touch it and it will be hot. To have them not able to close off leaves them in an open circuit. That will make a lot of heat!

 

[Bill Martin]

Thanks, Art. No, this gets super hot. The last time there was some smoke just before I turned the key to shut it down. It appears now that the new solenoid that I just installed is shot (no signature "click" when I turn the key on).

I've since determined that the solenoid isn't being "overworked," since it's basically just injecting the plunger once into the fuel injection device when I turn the key and then pulling the plunger out once when I turn the key off to stop the flow of fuel and shut the tractor down.

Note that no fuses are being blown, certainly not the 30amp solenoid fuse. So I'm beginning to think that maybe I just got a bad solenoid with an internal circuitry-wiring problem that permitted it to overheat and burn out.

Finally, note that that when the original solenoid went out it was blowing fuses.

So I'll be talking to the Kubota parts guy today to see if he can shed any light on things. I have been led to believe that it is not unusual to get a sour solenoid right off the parts rack.

Let me know if anyone else has experienced this problem and I'll stay tuned. Thanks. Bill

 

[art]

It's a simple system and our parts system shows that we have not moved any. I'd wonder if the rack in the pump might be the issue.

 

[Nicb7800]

Bill

I know that this is quite a old post and I was wondering what you might have found out about the solenoid? Because I am experiencing the same issue almost to the T. My problem is after I shut it off, I cannot get it to start unless I keep my key in the on position, and jump the white wire on the battery post until it clicks. Then it fires up??????? I'm just a little confused, because my solenoid also gets hot like to the point you don't want to touch it. So let me know if you ever found out what the problem was. Thank Nic