12.5 kw gen problems kind of

[MTK46]

Kind of have a problem with my generator. Onan generator has just over 1800 hours. Had been services when I bought it 3/3/17. So here's what it does. Starts right up runs for maybe four five minutes & then shuts down. Load no load doesn't make a differences. Starts right back up and than does the same thing. Might run a little longer the second time. Shuts down just like you turned the switch off. Makes no difference which switch you use. Will do the same thing on the third try. After that runs fine. Will do this after it sits over night or after traveling. Oh yea fuel tank is full, it just shuts down like you turned it off. I'm a 40+ year mechanic & this has me Runs great ones it does it's dying act.

[gemert]

Originally Posted by MTK46

Kind of have a problem with my generator. Onan generator has just over 1800 hours. Had been services when I bought it 3/3/17. So here's what it does. Starts right up runs for maybe four five minutes & then shuts down. Load no load doesn't make a differences. Starts right back up and than does the same thing. Might run a little longer the second time. Shuts down just like you turned the switch off. Makes no difference which switch you use. Will do the same thing on the third try. After that runs fine. Will do this after it sits over night or after traveling. Oh yea fuel tank is full, it just shuts down like you turned it off. I'm a 40+ year mechanic & this has me Runs great ones it does it's dying act.

Oil level? Fuel filter? Other than those you may be suffering a control issue. It is programmed to shut down under some circumstances related to the generator itself and the power produced. Good luck.

[Mr_D]

If the controls don't detect power from the generator section it will shut down as Jerry said. That would be my suspicion.

[Steve Ownby]

Originally Posted by gemert

Oil level? Fuel filter? Other than those you may be suffering a control issue. It is programmed to shut down under some circumstances related to the generator itself and the power produced. Good luck.

If it shuts down due to the control board seeing a fault then it should throw a fault code. If no blink code on the start switch then I would suspect a fuel issue of some description. Air in the fuel line or the lift pump beginning to fail.

[MTK46]

Start switch doesn't blink when it shuts down. Oil level is fine & if that was the problem why would it stay running after three tries? I don't think by looking at it that the fuel filter got changed when the service was done. Anyone have a after market # for it?
I was thinking it could be the lift pump. It just starts so fast on all the tries which sure doesn't sound like a lack of fuel. Is the lift pump on the gen engine or a electric pump ?

[Steve Ownby]

Originally Posted by MTK46

Start switch doesn't blink when it shuts down. Oil level is fine & if that was the problem why would it stay running after three tries? I don't think by looking at it that the fuel filter got changed when the service was done. Anyone have a after market # for it?
I was thinking it could be the lift pump. It just starts so fast on all the tries which sure doesn't sound like a lack of fuel. Is the lift pump on the gen engine or a electric pump ?

The lift pump is in the bottom rear on the driver's side and its electric. If you look at the rear, you will see the fuel supply and the fuel return line side by side. The lift pump is just inside the genset case.

Next time you crank it, from any start switch, hold the bottom of the switch down for a full minute or so. You should hear the pump running. It makes an audible "click" when it runs. Just thinking that if air is getting in the line at some point between the pump and the tank, that might pump it out.

[MTK46]

Thanks Steve I'll give that a try.

[Outbound]

Not sure if your generator has a bad oil pressure switch, maybe when it comes up to full oil pressure the pressure switch bellows fail and it cuts out on low oil pressure, I had a boat that would stall when oil pressure raised try by passing switch. Your problem sounds like a safety switch is failing.

Outbound
2002 Monaco Executive

[MTK46]

Thanks again Steve for your great advise! After work yesterday I went out & used the switch on the generator. Primed the fuel system before I started it. Fired up & ran with out dieing. Being as the fuel pick-up line is 15 years old
yea it's getting air into the system. I'll put that on my to do list but it's not at the top of the list.

[gemert]

Originally Posted by Steve Ownby

The lift pump is in the bottom rear on the driver's side and its electric. If you look at the rear, you will see the fuel supply and the fuel return line side by side. The lift pump is just inside the genset case.

Next time you crank it, from any start switch, hold the bottom of the switch down for a full minute or so. You should hear the pump running. It makes an audible "click" when it runs. Just thinking that if air is getting in the line at some point between the pump and the tank, that might pump it out.

Steve, your advice obviously worked but I'm a little confused. When you hold the switch down the clicking indicates that the generator is being primed. Then after a few seconds the genny starts. You are saying to continue holding the switch down so I am assuming that the starter cuts out automatically when it starts, but the lift pump continues to run at a higher than normal speed. Is that the case? Thanks
Jerry

[MTK46]

Originally Posted by gemert

Steve, your advice obviously worked but I'm a little confused. When you hold the switch down the clicking indicates that the generator is being primed. Then after a few seconds the genny starts. You are saying to continue holding the switch down so I am assuming that the starter cuts out automatically when it starts, but the lift pump continues to run at a higher than normal speed. Is that the case? Thanks
Jerry

Jerry no what Steve is saying & what I did is hold the gen button down in the off position. That will turn on the fuel pump. I held it down for a minute & then pushed the start.

[bruceisla]

Originally Posted by MTK46

Jerry no what Steve is saying & what I did is hold the gen button down in the off position. That will turn on the fuel pump. I held it down for a minute & then pushed the start.

As mentioned, depressing/holding the "Off" side of the rocker switch activates the pump.

[gemert]

Oh! Got it thanks.