Gas in my oil

Frank Sorbello · Aug 16, 2016

Couple months ago I installed new 25hp Kohler in my 422. My Dad was in a very serious car accident 2 months ago so the tractor has been parked since then. I leave the hood up when I am not using the tractor. I noticed gas level dropping a little. I have a valve under the gas tank and before fuel pump. It has been shut off. I pulled dipstick and smelled gas. Very thin oil. I drained the oil, very thin with smell of gas. The tank still has gas in it and i have the fuel line with the valve shut off going in to a glass jar. So far no gas in the jar. The engine has one hour on it. I am puzzled.

MossRoad · Aug 16, 2016

Me too! If you've operated the shut-off valve since the suspected event, you may have gotten it to shut off completely now and may never see a bypass again. Maybe fill the tank to the level it was before the event, to see if the added weight of the fuel in the tank pushes gas through the closed valve? Just thinking out loud.

MossRoad · Aug 16, 2016

Oh, and hope your dad is recovering.

KentT · Aug 17, 2016

The shutoff valve should've prevented it. Be aware that if your fuel pump diaphragm starts to fail, it will allow gas to seep into the valve cover and into the engine. In almost 1409 hours on the Kohler 25hp, I had two fail. Last time it failed I went to a low pressure electric pump, rather than spending another $100+ for a factory Kohler pump built into the valve cover.

A stuck float or needle valve in the carb will also allow gas to seep into the cylinders, then down by the rings into the crankcase. I do not like Kohler fuel system nor the gravity feed plastic tank...

Frank Sorbello · Aug 17, 2016

Moss, I put a few more gallons of gas in the tank. I haven't touched the valve at all. I have the end of the hose in a jar. Do you think the heat from being in my pole barn, pressurized the gas vapors to build enough pressure to push through the closed valve up through the fuel pump in to the carb. I can not figure how that gas got in the oil. I literally have .4 hours on this engine.
Dad is recovering. Broke his neck, back in two spots, had a pulmonary embolism, minor heart attack, stroke, and pneumonia all while in the hospital. Off the ventilator still on a feeding tube. Hasn't had anything to drink since June 18th. Literally begs anyone and everyone for a drink of water.

Kent, do you think I could have a stuck float with a complete brand new engine? Is the low pressure electric fuel pump the way to go?

Thanks
Frank

KentT · Aug 17, 2016

On a brand new engine, I'd suspect the carb float or needle valve being stuck, rather than a defective fuel pump. Ethanol gas is VERY hard on fuel systems when it sits in there for long periods of time. It has caused the outdoor power equipment and marine industries all kinds of problems, due to the seasonal use of those types of equipment. As long as you're using it up and replacing it with fresh fuel, such as in your car, it doesn't cause nearly as many problems.

MossRoad · Aug 17, 2016

Frank Sorbello said:
Moss, I put a few more gallons of gas in the tank. I haven't touched the valve at all. I have the end of the hose in a jar. Do you think the heat from being in my pole barn, pressurized the gas vapors to build enough pressure to push through the closed valve up through the fuel pump in to the carb. I can not figure how that gas got in the oil. I literally have .4 hours on this engine.
Dad is recovering. Broke his neck, back in two spots, had a pulmonary embolism, minor heart attack, stroke, and pneumonia all while in the hospital. Off the ventilator still on a feeding tube. Hasn't had anything to drink since June 18th. Literally begs anyone and everyone for a drink of water.

Kent, do you think I could have a stuck float with a complete brand new engine? Is the low pressure electric fuel pump the way to go?

Thanks
Frank

I don't know... maybe the shutoff valve was just not closed all the way. The gas tank should be vented, and that would prevent any pressure. Does it ever hiss when you remove the filler cap?

As for your dad.... OUCH! Hope he recovers quickly. :thumbsup:

Bird · Aug 18, 2016

A stuck float or needle valve in the carb will also allow gas to seep into the cylinders, then down by the rings into the crankcase.

I've had gasoline get into the oil in the crankcase twice in my life. The first time, about 1970, was a year or so old Toro lawnmower with a Tecumseh engine. The dealer told me I'd have to have a complete engine, so I got rid of it. I later had doubts about his honesty and competence. The second time was about 1998-99 with an old 3.5 hp Briggs & Stratton engine on a spray rig. I replaced the carb and that fixed it.

Frank Sorbello · Aug 25, 2016

I called Equipatron, the online store where I bought my Kohler engine. They suggested I call Kohler. When you call Kohler they ask for a zip code then redirect your call to an authorized Kohler retailer. There must be a logical explanation why I am get gas in the crankcase in a brand new engine. It has a 3 year warranty, but the very last thing I want to do is pull the engine out of my PT-422 again.
Mitch at Equipatron talked to Kohler technician. He thinks the fuel pump is putting the gas into the crankcase. Oddly enough my Uncle said the same thing to me last week. Any thoughts on this?
Thanks
Frank

MossRoad · Aug 25, 2016

Yeah. I have some thoughts. No facts. Just thoughts... :laughing:

Isn't the fuel pump driven by something under the valve cover? If the fuel pump leaks into the valve cover, wouldn't the fuel go into the oil?

I suppose even if you have a fuel shutoff valve between the gas tank and fuel pump, once you shut off the engine, if the fuel pump is leaking, any fuel left in the lines, filter, etc... after the fuel shutoff valve could leak into the area under that valve cover.

And I also suppose that with the tractor sitting for that long, even with the fuel valve shut off, that gas tank is vented, and maybe with the heat in the garage the fuel has evaporated some after the two months?

Just thoughts.