Generator gas overflow even after changing regulator

[jimdmorrison]

Replaced my generator with an onan qg 4000 gasoline generator. Gas is getting into the oil and into the air filter when it overflows. It pressurized the oil tank. Checked the fuel regulator and it wasn’t changing pressure. It was 6 psi no matter what. Replaced that and it’s still at 6. Any ideas?

[wolfe10]

Sounds like a leak past the CARB NEEDLE AND SEAT.

Could high fuel pressure be a contributing factor? Sure.

But can't imagine how it could run smoothly with fuel mixture that far out (raw gas pouring into the intake and air cleaner).

Were this a mechanical fuel pump where the "back side" of the pump is lubed by engine oil, that would be another pathway, but not with an electric fuel pump.

[jimdmorrison]

time2roll wrote:
Is it the carburetor that is overflowing? Get a new one.

I already replaced the carb. It was the wrong size fuel pump. But I still can't figure out why it's building oil pressure and not letting me fill it.

[jimdmorrison]

"HOW do you think the fuel is getting to the Crankcase?"

That's a very scary question. I have no idea. It's so weird that it builds pressure in the oil chamber any time I try to start it, and that after draining, I couldn't get more than half of the oil capacity in there. 1.6 quarts is what it is supposed to be.

[dougrainer]

jimdmorrison wrote:
So the previous owner had put the wrong fuel pump on. I replaced that, so I think that solved the gas issue. Still having a weird issue with the oil pressure. I drained it and I can only get half a quart or so in. It’s weird that it builds oil pressure.

The reason I asked is simple. ONAN fuel pumps even tho they LOOK like other aftermarket fuel pumps are LOWER PSI pumps. So, people buy and install that CHEAPER than Onan fuel pump with the higher PSI and they may have problems. Not always, but you have an unusual problem. Remember ALL the fuel pump does is force GAS to the Carb bowl. THEN the Float needle jet opens and closes the fuel to the bowl. IF you have TOO MUCH fuel, then the Onan will not run(flooded). So, HOW do you think the fuel is getting to the Crankcase? Doug

[jimdmorrison]

So the previous owner had put the wrong fuel pump on. I replaced that, so I think that solved the gas issue. Still having a weird issue with the oil pressure. I drained it and I can only get half a quart or so in. It’s weird that it builds oil pressure.

[time2roll]

Is it the carburetor that is overflowing? Get a new one.

[dougrainer]

Onan fuel pressure is 3.5 to 4.0 psi. Is this a brand new Onan or one you purchased used. Doug

[markchengr]

You're experiencing fuel dilution of the crankcase oil. Could be one or more broken rings or a cracked piston. Sounds like a factory defect. Have seen this on large engines. -Mark.

[jimdmorrison]

Could it be the fuel pump?