Generac starts, runs while "start" button pushed, but dies when I let go.

[jmebonner]

I just had the carb cleaned on this, it was out of the RV when I got it.  As I got everything hooked up and pressed start after priming, it fired right up.  However, when I let the start button go, it dies in short order.    It's an older generator, most likely a 93 or 94.  Model 09557-4, Series NP30g. 

Any idears what a fellow should try?  By the way, the oil is full

Thanks!
James

 

[RLSharp]

However, when I let the start button go, it dies in short order.

Sounds like your voltage regulator. If no 120 VAC is sensed, the genset shuts down.

Richard

 

[JIGGS]

Mine did the same thing. It was the voltage regulator. There is a great trouble shooting chart. I just went blank on the name of it. It has been mentioned here before. Hopefully someone will give it again.
I goggled onan generator want start and found it

 

[jmebonner]

Thanks for the replies.  To test the regulator is it as simple as having someone hold the run switch and seeing if the microwave comes on?

Unfortunately, a quick search for a VR on this model comes up blank   I do have a rolling 5k Coleman generator that the guy threw in w/ the RV, but I was hoping for a self contained one for ease of use.

 

[Gary RV_Wizard]

The starter switch sends 12vdc power to the fuel pump for priming and bypasses the interlocks for low oil pressure and 120vac output. If it cuts off when you let go of the switch, it could be any of those things that is shutting it down.

 

[Jeff]

We have a diesel Generac that exhibited the same characteristics and it was a dirty, loose connection on the remote start harness running from the generator and the dash. I disconnected the snap together connector, sprayed it with contact cleaner, reconnected and have had no problems since.

 

[Nancy_Troy Russell]

Ours did the same thing. Turned out it was dirty (rusted) brushes so it could not create enough energy which causes the gen to not run (we were told it is a feature to keep the gen from damaging itself). Once the brushes were cleaned it has worked like a charm for the last 3 years, putting out more power now than ever - like new again. Too many years living in Washington state I guess -  ;D

Note that as another porster mentioned, dirty or loose connections could cause the same thing since it must generate enough power to trip the sensor allowing the gen to continue to run.

Troy R.
Concord, Ca
1995 Safari Sahara
2003 Sport Trac Toad

 

[boatbuilder]

As Gary said when the start switch is pressed the low oil pressure shutdown is bypassed.  I know that the small portable Generacs had a problem with the diaphragm in the low oil switch cracking and not opening.  If you pull the wire off the low oil switch and it starts and stays running then that is your problem.  The low oil switches are inexpensive and easy to replace.

 

[jmebonner]

Thanks again for all the input.  It's raining to beat the band here, when it stops (they're saying Sunday), I'll give it a look-see.

 

[JIGGS]

Don't do like I did. I burned up the starter holding the starter switch in to keep it running.

 

[LeeCI]

    U might want to take a look in The RVers Corner . net I believe. There is a extensive piece on their tech bout the same problem. A onan tech wrote out a number of things u may want to check out. P.S mine does the same thing on occasion.