BAC Forum

General Boards => Technical Support => Topic started by: Bobby Kirk on December 21, 2022, 05:07:24 PM

Title: Onan 12500 Generator
Post by: Bobby Kirk on December 21, 2022, 05:07:24 PM

My coach is a 2006 Beaver Marquis.  the Gen hours meter quit working.  The run light inside coach on Gen start switch quit working so I am unable to check error codes.  Gen was shutting down after about 30 mins. Had the belts, heat sender, thermostat changed.  Ran gen for about 1 1/2 hr and it shut down, but engine does not appear to be hot.  Can not check error code could engine be getting false info from circuit board??? Thanks for the help. Love the FORUM.

Bobby Kirk

Title: Re: Onan 12500 Generator
Post by: Fred Brooks on December 21, 2022, 05:53:55 PM

    Bobby,
Sometimes the replacement belt they use is wrong. I would run the generator and check the velocity of the blower air coming out from under the generator. It should feel like 40 to 50 mph. Fred

Title: Re: Onan 12500 Generator
Post by: Eric Maclean Co-Admin on December 21, 2022, 07:22:23 PM

Fred
If I'm not mistaken the blower is part of the flywheel assembly and not belt driven .
I think the only thing the belt drives is the waterpump and possibly an alternator depending on model.

It is possible it's the wrong be?t of the belt has become loose .

Eric

Title: Re: Onan 12500 Generator
Post by: Eric Maclean Co-Admin on December 21, 2022, 07:27:58 PM

Bobby
The remote start switch , light and hour meter are all run from a wiring harness that is plugged into an external connection on the gen set your problem ( no hour meter or light is probably at that connector .
Yor should be able to get the codes off the switch / light on the gen set.
Eric

Title: Re: Onan 12500 Generator
Post by: Fred Brooks on December 22, 2022, 01:24:08 AM

   Eric, I thought the 12.5 kw was similar to my 10 kw when I changed the belt that drives the blower impeller. Sorry if I assumed incorrectly. Fred

Title: Re: Onan 12500 Generator
Post by: Bobby Kirk on December 22, 2022, 03:20:05 AM

Thanks for the input.  My gen is aa 3 cylinder  Kubota engine  It has 2 belts  one is just for fan only   I am going to check
tomorrow to see if it is blowing under gen as was suggested  Thanks again.

Title: Re: Onan 12500 Generator
Post by: Eric Maclean Co-Admin on December 23, 2022, 01:29:13 AM

Yes Fred after checking the service manual you are absolutely right that particular gen set uses two be!ts,
 the generator has the cooling fan mounted on end of the rotor and the other end has a pulley with a serpentine belt which goes over to the engine crankshaft this belt has a spring loaded belt tensioner  so if the ben set is making useable power the generator belt must be good and therefore the cooling fan must be turning as it is connected to the generator rotor.
However the engine has a separate belt which does nothing but drive the engines water pump.
That could be the loose or missing causing an over heat condition but there are other possibilities as well things like radiator fin blockage, thermostat stuck, faulty water pump blocked cooling passages etc.

The first thing to do is check the codes to find out why the Genset is shutting down it may be unrelated .

Thanks Fred for pointing that out I hate to send someone down the wrong path.
Eric

Title: Re: Onan 12500 Generator
Post by: Bobby Kirk on December 23, 2022, 02:11:14 AM

Thanks Fred and Eric for your input.  Have coach back home and will try to get codes on the Gen set.. Thanks again

BOBBY KIRK

Title: Re: Onan 12500 Generator
Post by: Eric Maclean Co-Admin on December 23, 2022, 02:51:12 PM

Bobby
The service manual for your gen set is in the coach assist library,  it has a  troubleshooting section to help you out.

Eric

Title: Re: Onan 12500 Generator
Post by: Bobby Kirk on December 23, 2022, 11:39:10 PM

 Thanks I have service namual not much help for my problem.  Thanks anyweay.