[Amel Yacht Owners] ONAN FAULT BRAKER

Bill & Judy Rouse <yahoogroups@...>

I think you are saying that the electric breaker is opening under load.

I am assuming that you are talking about the breaker on the side and near the rear of the Onan.

Can you confirm that the breaker is opening?

I assume that not only is the breaker opening, but the engine is stopping and it happens when a load is added and not before.

I would guess that you have a fuel problem. When was the last time you changed the fuel filter? What about the fuel pump? They have a life of about 2000 hours. What are your hours on the fuel pump?

The reason I am guessing a fuel problem is that the generator is designed to run at a constant RPM. As the load increases the governor will attempt to keep the RPMs stable, but this requires more fuel to the cylinders. When it cannot keep the RPMs stable because of the fuel problem, the engine speed reduces because of the extra load and not enough fuel to compensate. As the speed reduces, so does the voltage which causes an increase in amperage, throwing the breaker and killing the engine.

All of that said, remember it is a guess with very limited information from you.

I hope that this might help you.

You probably should get an Onan mechanic to look at it.

Bill Rouse
BeBe Amel 53 #387
Currently at Barcelona
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+39 333 121 8115 Italy Mobile
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On Jul 12, 2015 8:03 PM, "osterberg.paul.l@... [amelyachtowners]" <amelyachtowners@...> wrote:

Have problem with my Onan
It starts alright but stops after 5-10 minutes depends on how hard I load it. If I run the AC it,s stop emediatly. By reseting the falt breaker I can start again after a while. Does anyone know what can cause the problem
Paul on SYKerpa #SM259

Bill & Judy Rouse <yahoogroups@...>


I think that you are talking about the *Emergency Stop Switch*, if it is on
the front panel. There should also be a DC voltage breaker on the front
panel. The AC line breaker (breaker that an over-load would cause to open).
While you are facing the front of the Onan, the AC line breaker is on the
left side, near the rear.

Is switch (breaker) that is opening labeled "Emergency Stop Switch?" See
the attached photo.

If this switch is opening, it probably is a faulty switch because as far as
I know, the switch is designed for the owner to cut the generator OFF in an
emergency or to keep it OFF when servicing. BTW, I sometimes accidentally
hit this switch when I am in the engine room while the generator is not
running. The next time I try to start the generator, nothing happens. It
took me a while to solve this the first time.

Let me know

BeBe 387
Currently Barcelona

On Mon, Jul 13, 2015 at 11:24 AM, Paul Österberg <osterberg.paul.l@gmail.com
Hello Bill
The fault breaker that "close down " is the tiny red one with a
transparent rubber cover between engine hour counter and the starter switch
on the Onan
I have currently 1320 h on the genset new fuel filters and impeller
When it stops i does it very suddenly
It looks as adequate amount of cooling water is comming
But general felling it is a hot engine
Could it be the heatexchanger?