Skip to main content ↑ ↓
Topic: Generator solenoid (Read 775 times) previous topic - next topic

Generator solenoid

My generator (7.5 KW Onan Diesel) starts fine and runs for about 15-20 minutes then dies.  It then won't start again.  After about an hour, it will start again and run for 10 minutes and die.
The fuel filter is clean and is fairly new.  After looking over the generator, there is a solenoid on the front of it that appears to be bad and I suspect this is the problem.  What does this solenoid do?
Thanks,
Kearn
Kearn
'92 U300 40 ft.  WTBI  6V-92  #4130
GMC Yukon toad
'08 Casita Spirit Deluxe 17ft

Re: Generator solenoid

Reply #1 –
Do you have a picture of the suspect relay?
Regards,Irwin
Irwin

Re: Generator solenoid

Reply #2 –
Symptoms are what I would expect from an overheating problem. Check coolant and cooling systems.
J D Stevens
1997 U295 CAI 36' Build #5085
2002 Subaru Outback
Motorcade 16869
Bellville, TX

Re: Generator solenoid

Reply #3 –
I suspect that is the fuel shutdown solenoid.  It needs a signal to open, and another to hold it open.  This would affect start-up, but wouldn't cause a delayed shutdown.  I would look at possible overheating conditions.
Regards,
Brett

'99 42' Foretravel Xtreme
'14 Brown Motorsports Stacker
'05 Chevy SSR
'02 BMW R1150R

Re: Generator solenoid

Reply #4 –
The cooling system has a temperature sensor.  Check your thermostat and coolant level.  It's possible that if its not opening, the coolant temperature is building up, causing the sensor to shut down the Onan. 
Don Hay
'92 Grandvilla, U-280
The Hayfever Express
Build #4055
'97 GEO Tracker
Life is like licking honey off a thorn.

Re: Generator solenoid

Reply #5 –
Quote from: 4stakes –
What does this solenoid do?
I have the same generator.  As others have said it's the fuel solenoid.  It has to be pulled in for the engine to run.  When you manually crank it from the control panel (box that is on the generator), you should see this solenoid pull in WHILE it's cranking and running.  When it dies, try re-starting right away and notice if the solenoid is being pulled in.  If so, it's a fuel supply issue.  If not, it's a wiring or solenoid going bad issue.  But this just my own thinking, I'm no expert.  You can also manually pull the solenoid in to see if it will start.

As for overheating, when that happens it pops a red button the panel and cuts power to this solenoid.  I believe the button is labeled "FAULT".  If you don't reset it, it will crank but not start.  A fault can also be caused by low oil pressure IIRC.  I assume you have checked coolant and oil levels.  How about fuel level in the tank?  Above 1/4 tank?
John Fitzgerald
1991 U300 (SAI) Side Aisle Island Bed 40'
Detroit 6V92 with Allison Retarder
Meridian (Boise), Idaho

Re: Generator solenoid

Reply #6 –
Actually, the temperature sensor is at the top right of the Onan, next to the top radiator hose.  You can see wires going to/from it.  I should, but don't know where the thermostat is located.
Don Hay
'92 Grandvilla, U-280
The Hayfever Express
Build #4055
'97 GEO Tracker
Life is like licking honey off a thorn.

Re: Generator solenoid

Reply #7 –
John is correct: The Red Fault button on the front of the box would have to be pushed back in if it's a temperature problem.  Otherwise it wouldn't start, even when antifreeze has cooled down 10-15 minutes later.  If the button isn't popped out, it's probably not a temperature issue.  I had the fuel shutoff solenoid crap out last spring, after 22 years.  Guess I shouldn't complain :)
Don Hay
'92 Grandvilla, U-280
The Hayfever Express
Build #4055
'97 GEO Tracker
Life is like licking honey off a thorn.

Re: Generator solenoid

Reply #8 –
Member Coastprt just posted about replacing the fuel pump: What did you do to your coach today III Reply #535
Another possibility.
John Fitzgerald
1991 U300 (SAI) Side Aisle Island Bed 40'
Detroit 6V92 with Allison Retarder
Meridian (Boise), Idaho

Re: Generator solenoid

Reply #9 –
FanBelt loose or broken

Re: Generator solenoid

Reply #10 –
Now would be a good time to replace the fuel shut-off solenoid, start solenoid, fuel pump, etc., etc..
Flush the cooling system (RMI 25),  replace the fuel lines

Especially if you enjoy piece of mind.. pc 
S/W Houston 95" U320C SE/40' 
Build #4778  Cummins M11
Repairs & Covered RV Parking (BAO)
PPL is close..

Re: Generator solenoid

Reply #11 –
Thanks for the replies.
Fluids are good and the temperature fault button has not had to be reset.  Belts are good and tight also.  Fuel tank is full. 
My plan is to change this solenoid first and see if that fixes the problem.  I just was not sure what its job was.
Thanks again for the suggestions and I hope that replacing it solves the problem.
Kearn
'92 U300 40 ft.  WTBI  6V-92  #4130
GMC Yukon toad
'08 Casita Spirit Deluxe 17ft

Re: Generator solenoid

Reply #12 –
A left field idea, this was like a problem a friend of my had. The fuel supply line was bad inside, not letting a steady flow to the apu.
George Ray 1992 U280 40'

Re: Generator solenoid

Reply #13 –
Quote from: JohnFitz –
I have the same generator.  As others have said it's the fuel solenoid.  It has to be pulled in for the engine to run.  When you manually crank it from the control panel (box that is on the generator), you should see this solenoid pull in WHILE it's cranking and running.  When it dies, try re-starting right away and notice if the solenoid is being pulled in.  If so, it's a fuel supply issue.  If not, it's a wiring or solenoid going bad issue.  But this just my own thinking, I'm no expert.  You can also manually pull the solenoid in to see if it will start.

As for overheating, when that happens it pops a red button the panel and cuts power to this solenoid.  I believe the button is labeled "FAULT".  If you don't reset it, it will crank but not start.  A fault can also be caused by low oil pressure IIRC.  I assume you have checked coolant and oil levels.  How about fuel level in the tank?  Above 1/4 tank?


I have a Kubota V1305 4 cylinder Kubota and was having similar problems with hard starting and shutting down after running a while and then finally it would start and shut down immediately. I thought maybe the fuel lines needed replacing ( which they probably do). This has been going on for a while and I would just bleed the air out of the fuel line and it would run okay but not great for any length of time. 

Oil and coolant levels were okay. I pulled the fuel shutoff solenoid immediately after starting manually before it had a chance to die and it ran perfect.  Inserting the relay back in would shut it off. I tested it that way several times and let it run for a couple of hours with no problems!

Ordered a new solenoid from Ebay 12V Fuel Shutoff Solenoid for Kubota D905 D1005 D1105 V1205 V1305 V1505...  and replaced it today.  Started immediately from the dash switch and ran great for an hour with a full load (both A/Cs) with no sputtering or shutdowns.   

The old solenoid was probably on its way out for a long time and was working intermittently enough to fool me.   

Thanks John for the excellent tech tip on how to troubleshoot the generator fuel shutoff solenoid!  It's an easy an inexpensive fix that everyone should know to eliminate a potential generator problem before going on to something else.  A new spare to carry onboard along with other spare relays would be a good idea!

Jerry

The selected media item is not currently available.
Jerry and Cindy Maddux
1993 U300/36WTBI DD6v92TA
build 4271  "Miss Lou"
1995 suzuki sidekick 4x4 toad
Gulfport, Ms

"Pride of Ownership"