Community Forums

The Farmer · 10-15-2022, 08:45 PM

1995 American Dream Coach
8KW Onan Generator
Increasingly difficult to start generator. I have to hold down the prestart switch for 45-60 seconds before it starts and it used to be only 20 seconds. Also seems to be getting worse. Replaced the generator battery and both chassis batteries and all the coach batteries recently. Just replaced the oil filter and changed the oil.
Ideas?

1972VWbus · 10-15-2022, 09:41 PM

I'd change the fuel filter.

How long since you changed the spark plug/s?

153stars · 10-16-2022, 06:11 AM

Is it cranking slow? The cables and ground are first step.I needed new starter it was just too tired.
Does it smoke a lot and miss after starting. The glow plugs don't last forever. You can find actual OEM I think Bosch for 75% cheaper than same from Onan.

craigd853 · 10-16-2022, 06:16 AM

Quote:

Originally Posted by The Farmer

1995 American Dream Coach
8KW Onan Generator
Increasingly difficult to start generator. I have to hold down the prestart switch for 45-60 seconds before it starts and it used to be only 20 seconds. Also seems to be getting worse. Replaced the generator battery and both chassis batteries and all the coach batteries recently. Just replaced the oil filter and changed the oil.
Ideas?

Hello, is this a gas or diesel engine? If gas check to make sure choke is fully closed when starting cold. If this checks good I would clean your carb or buy a new one they are less than 100.00 dollars on Amazon or if you are mechanically inclined carefully take your carb apart and pull the jet out and clean it so as to be able to see all of the tiny pinholes that are in the jet. Hold it up to a lighted area to be sure. Also like one of the previous posters said check, clean and regap plus. If they look worn down best and easier just to replace. My guess is out of adjustment choke or clogged jet. Good luck

The Farmer · 10-16-2022, 04:30 PM

I am new at this forum concept and missed an important detail.
It is a diesel generator.
I did change the fuel filter and no change.
Now what?
It seemed to me it was something that was taking longer to get going such as a glow plug or fuel pump priming.
The Cummings rep I talked to at a show told me the glow plugs don't go bad slowly, they either work or they don't. I don't even know if it has glow plugs.

andy29847 · 10-16-2022, 04:40 PM

Glow plugs and the glow plug controller can be tested. Mine tested good and I replaced them anyway. My hard to start trouble did not go away. I finally resolved to clean all electrical connections. I found corrosion and a loose fuse holder on the fuse for the glow plugs. On my Quiet 7500 Oman, this fuse is under the plate of the control box on the generator.

MrMark52 · 10-16-2022, 04:41 PM

It’s diesel, it has glow plugs - it DOESN’T have spark plugs. ��

A little tenacious search g and you can find a copy of the Owner, Service, and Parts manuals for download. Those will go a long way to helping you live with your generator. ��

Argosy · 10-17-2022, 04:05 PM

You really need to figure out what engine is in it. My 7500 has the same engine as my Kubota tractor, that was a real stroke of luck. Once you know the engine you can find a manual and forum where hard start has probably been discussed.

153stars · 10-18-2022, 04:57 AM

Pretty much all Onan genny service and diognostic manuals are available online. They have troubleshooting flowchart and testing procedures to prove or fail individual components causing issue. Eyes on and observations to things like glow plug fuse mentioned never hurts.