Onan generator

[flydixie1415]

Ok any thoughts would be appreciated.

We are having a problem with the generator not pulling fuel from the tank. Here is a list of the things we have done so far.

1. Changed the complete fuel filter system.
2. Replaced the fuel hose from the tank all the way to the fuel filter
3. Added a check valve to fuel hose
4. Changed the fuel pump.
5. Fuel tank is at least half full
6. Have used 5 gallon diesel cans and it runs just fine.

Never had a problem for 19 years with pulling fuel from tank. I have thought of added a lift pump from the tank.
Not sure if it should be added at the fuel tank or the generator end.

Need to address this as soon as possible. Thanks for any help

 

[rsmith]

Check the fuel pump again. I’ve seen new old stock ones with holes in the diaphragm. Happened to me when I put on my spare pump.

 

[SKYCHENEY]

Can you pull fuel from the tank with a pump? Could the pick up tube be cracked or broken off?

 

[Jims43DC]

Can you pull fuel from the tank with a pump? Could the pick up tube be cracked or broken off?

This was my first thought also .. that the drop line inside the fuel tank may be broken

 

[Pascal]

If it runs off a 5 gal tank the problem is either in the pick up or the lines.

You can try using a priming pump to pull fuel out of the tank and send it to the gen and see what happens

10 days ago one of the two 2004 45kw Onans on the 116 i run started shutting down very quickly under full load. Major pita here in the Exumas as we re on the hook almost 24/7. The boat has a priming pump for each engine and gen. That gen would run fine with the priming pump on. I replaced the gen fuel pump and all Is good.

I was surprised that the gen would just shut down clean once a load was applied, I would have expected a fuel pump issue to result in some hunting, freq drop before shutting down but it didn’t.

 

[whoover]

Check the pickup in the tank. I pulled mine and it was bent and cracked. Who ever installed it in the past did not get the lower end in the holding tab at bottom of the tank. Years of fuel sloshing around bent and cracked it. Anything below 1/2 tank and the gen set would suck air. It would run but not have any output.

Walt Hoover

 

[rsmith]

Mine did the same thing once the forward tank got below half tank the generator would die. Ran fine off a fuel can. Turned out to be the pump after I spent a lot of time looking at the tank pickups. If it’s an older onan it has the pump with the integral primer lever. The cam can wear to the point where it works but won’t provide enough lift.