onan -DANGER THIS IS LONG WINDED!

richard waters

New member
Feb 8, 1999
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> I am however getting very tempted to throw mine into
> the pond out in the back of my place and let the fish
> live in it."
>
> Have your replaced the condenser yet - My 4 kw Onan
> drove me crazy with an intermittent problem - that was
> finally cured when I replaced the condenser. It would
> run for a while then start to run very rough (as the
> condenser started to fail when the unit got warmer)
>

Pete,
I didn't think of replacing the condenser. I even have a
condenser on hand. Its in a tune up kit I bought last year
but didn't use.

My main problem is that the governor doesn't do a very good
job of regulating the engine RPM as voltage demands change.

It'll be running just fine with a load, such as the water
heater and the A/C running. Then the water heater will drop
out when the water gets hot enough. At that time the RPM will
increase and cause the voltage to surge to well beyond the red
area (over 140 volts) of my voltmeter. I smoked my microwave
when that happened one time. Now I have to buy a new microwave
to replace the smoked one.

I also got smoke out of a surge protector while we were watching
TV with the genset running a few weeks after we smoked the
microwave. It burned the current limiting device right out in the
sure protector. Got a lot of smoke that time, but it apparently
did protect the TV!

Well anyway, the other day I tried to lube the governor arm that
goes into the engine with WD40. I did that because I started up
the Onan a couple of weeks ago when I went to visit the GMC at
the storage lot and it immediately went to high RPM. I found that the
governor arm was stuck in the high RPM position. I thought some
WD40 would free it up. It seemed to so I thought I had the problem
fixed. But, NO! last week I was at the storage lot again and I had
2 heaters going. I shut down one of them and it did it again. It
surged to over 140 volts again! I had to shut the Onan down because
I was afraid that it was going to blow out the Statpower 40.

So if I could get it to just maintain 1800 RPM regardless of the
electrical load I'd be in fat city.

Maybe I need a new governor spring or a new generator. I'm
starting to lean toward the new generator.

I don't know why I have these problems, I have a 22 year old
garden tractor with a 20HP Onan that runs great! My neighbor
has a 4KW Onan in his 23' and has never had a problem with it.

The PO even had the Onan rebuilt a few years ago.

The Onan has been the most problematic thing in my coach.

Richard Waters
'76 PB, Troy, MI
 
Richard,

I don't have much personal experience with the Onan (yet!), but what you're
describing sounds to me like a mechanical rather than an electrical problem.
I would take a good look at the throttle shaft, the linkage to the governor
arm and the governor shaft. The GMC Maintenance Manual also lists a lean
air/fuel mixture as a possible cause for governor surge/hunting.
Section 24C Page 5 Trouble Diagnosis
Section 24C Pages 25/26/27 Adjustments

Good Luck!

Peter
77 Eleganza II
Colorado

- ----- Original Message -----
From: "Richard Waters"
To:
Sent: Tuesday, February 29, 2000 9:30 PM
Subject: Re: GMC: onan -DANGER THIS IS LONG WINDED!

> > I am however getting very tempted to throw mine into
> > the pond out in the back of my place and let the fish
> > live in it."
> >
> > Have your replaced the condenser yet - My 4 kw Onan
> > drove me crazy with an intermittent problem - that was
> > finally cured when I replaced the condenser. It would
> > run for a while then start to run very rough (as the
> > condenser started to fail when the unit got warmer)
> >
>
> Pete,
> I didn't think of replacing the condenser. I even have a
> condenser on hand. Its in a tune up kit I bought last year
> but didn't use.
>
> My main problem is that the governor doesn't do a very good
> job of regulating the engine RPM as voltage demands change.
>
> It'll be running just fine with a load, such as the water
> heater and the A/C running. Then the water heater will drop
> out when the water gets hot enough. At that time the RPM will
> increase and cause the voltage to surge to well beyond the red
> area (over 140 volts) of my voltmeter. I smoked my microwave
> when that happened one time. Now I have to buy a new microwave
> to replace the smoked one.
>
> I also got smoke out of a surge protector while we were watching
> TV with the genset running a few weeks after we smoked the
> microwave. It burned the current limiting device right out in the
> sure protector. Got a lot of smoke that time, but it apparently
> did protect the TV!
>
> Well anyway, the other day I tried to lube the governor arm that
> goes into the engine with WD40. I did that because I started up
> the Onan a couple of weeks ago when I went to visit the GMC at
> the storage lot and it immediately went to high RPM. I found that the
> governor arm was stuck in the high RPM position. I thought some
> WD40 would free it up. It seemed to so I thought I had the problem
> fixed. But, NO! last week I was at the storage lot again and I had
> 2 heaters going. I shut down one of them and it did it again. It
> surged to over 140 volts again! I had to shut the Onan down because
> I was afraid that it was going to blow out the Statpower 40.
>
> So if I could get it to just maintain 1800 RPM regardless of the
> electrical load I'd be in fat city.
>
> Maybe I need a new governor spring or a new generator. I'm
> starting to lean toward the new generator.
>
> I don't know why I have these problems, I have a 22 year old
> garden tractor with a 20HP Onan that runs great! My neighbor
> has a 4KW Onan in his 23' and has never had a problem with it.
>
> The PO even had the Onan rebuilt a few years ago.
>
> The Onan has been the most problematic thing in my coach.
>
> Richard Waters
> '76 PB, Troy, MI
>
>
>