[Tfrazier]

So this is probably covered in a thread somewhere in here but I am not sure what to even look for.
Up to now, I have had zero issues with my generator (Kohler 12.5K). It has always started right off and has run smooth. 
This was not the case today. I noticed right off the bat that it was very sluggish when I tried to start it. It finally took hold and started then shut off. I tried again and the same thing happened. Strange.
I decided to start the engine and then tried the generator again. This time it started up fine and ran smooth. I shut the engine down and it  right on running (smoothly). I let it run for awhile and then shut it down. I gave it a few minutes then tried to start it again. Same thing as before (started then shut down). So I started the engine again and then the genny. It started right up and kept running after I shut the engine off. Anyone have any ideas as to what could be causing the problem? 

Thanks for your help.

[Fulltiming]

Sounds like your house batteries may be getting weak and need the extra voltage from the engine running to get the generator to spin over.

[Newell639]

I have same gen in our 02 and it runs same way at times won’t stay running. Isles down to about stalling then stalls out. Their a great gen but ours has never ever ran right. Ugh

[Richard]

I would check two things. First, replace all the fuel filters. Second, observe fuel shut off solenoid while the generator is misbehaving, sounds like it is not holding in. If those two dont cure it, check electrical connections to fuel pump.

[Tf175]

Does the generator run as long as starter is engaged , then stops when switch released?  If so it's something in the safety electronics or it's a little slow to start producing 12 v to keep running . Ours always takes a couple of tries and start switch held a little longer before it " takes hold " , relays latching I suppose . Your newer model may more modern electronics in the control system .
Good idea to change fuel filter at engine and check fuel /water separator as Richard says .
Seems like house batteries down per Michael as well. 
Gordon input probably very helpful. 
Chris

[encantotom]

what has been said are all things to check and do.

i have a post on the forum about my experience and it is slightly different, but thought i would share for you to have more info.

my genny is a powertech. which has a kubota engine.

when i first got it, the genny would run for ever sitting in my driveway. and then i was in town and didnt have 50a hookups so in the summer i ran the genny to power the air conditioners when i was working on it inside.

but.....as soon as i drove off, the power would turn on and off as the genny would stumble, then go back to running right and back and forth. so the power wouldnt stay on for very long.

back to the driveway and it would run forever, as soon as i drove off, it would start die down and back up over and over again.

the solution ended up being simple. the electric fuel pump mounted on the side of the genny passenger side front, had a check valve in it that was being funky. i replaced the fuel pump and it has run for years and hundreds of hours on the road.

just something else to think about if the other things dont help.

happy sunday

tom

[DK on the road]

My generator story may have some similarities or not. Thread found elsewhere on this forum. I have a Power tech 17.5kw gen set mounted DS mid chassis Reader Digest version.

I was having a problem staying running. It would start if cool, but if it had shut down on its own, I could only get it started using a electric prime pump switch next to the genny fuel pump.  If I left all the hush box doors open it seemed to help it run longer, but it wouldn't take a full load and would send it into limp mode, which  thru the main breaker as it idled down and did not stay running at designed speed and power output.  I called Power Tech, and they said, it was the fuel cut off switch, $ 600 later I felt like it helped, but once full power was asked of it, it went into limp mode and eventually shut down. I called PowerTech back, They said my control board was bad. They sent me a new one for est $500. I was thinking it helped, but it didn't, same as before.  If I ran the Cat engine, the genny would run longer but still would'nt take a full load. Our electrical engineers could tell me why, but I think the engine alternator was assisting the Inverter and giving support to what the genny couldn't do.


After 2 years and  about 9 months in the coach and 40K miles, I was frustrated, My wife began to hate the Coach. I took it to an authorized Power tech Generator company $1,600 and 5 days in there shop later, and 15 minutes down the road and same results as before. I took it back, and had a very good conversation with the company. They discovered that the new Fuel control solenoid I purchased from Power Tech,  and I installed, was bad. 

Now, about 5K miles, & 200 genny hours. No problems. Circled is the fuel pump solenoid that failed.    

[folivier]

Dave is that the fuel pump solenoid or the fuel stop solenoid?
If the stop solenoid isn't getting proper 12 volts to hold it open it could flutter and cause a shutdown or bad running. This could be part of Tony's problem.

[DK on the road]

Forest, I stand corrected. Good catch.

It is the Fuel stop solenoid.  That's why I like belong to this group. So many of the Guru's can direct us to solutions by naming the parts, and possible solutions.

[bestgenman]

I certainly may be incorrect here but, I think Dave’s PT set had isochronous governing.  The stop solenoid is removed and replaced with an electronic actuator which acts directly on the fuel rack of the injection pump..  it has a spring pushing the rack to the no fuel position when power is removed.  It uses PWM when operating delivered from an engine speed controller.  The engine speed controller receives a signal from a mag pickup.   If Dave has a MPU, it is likely an Isoc governed engine.  I’m sorry if I’m rambling here...but it could explain some of the erratic operations.  They are very temperamental.  I remember Dario Framchiti’s coach (785) had one,  it came in here for repair and I removed the electronic portion and that stopped all the aggravation.