gas getting in oil pan again, can anyone Help ?

[johann]

I am having problems again with my Scotts/John Deere 1642 . I have gas getting into the oil pan and then mower just pukes out. last time it happened two months ago it started to just puff oil on start up then turned progressivly worse over time until it just blew out so much oil and gas through the exhaust pipe that it would not run. I tuned up the carb, changed plug, oil,oil filter,and gas filter, gas cap.It ran like a champ, until now. this time it just went straight to blowing gas and oil out the front through the exhaust in the middle of mowing. This machine is 10 years old, and worked year round until last year, now it just mows the lawn, no leaf clean up , no more plowing snow. Could it just be the motor has run its course? Too many hours? it is a kohler.

 

[jinman]

The most likely suspect is the fuel pump. It uses crankcase pressure to operate. If the bladder inside the pump is cracked, it could be drawing fuel directly into the crankcase. The other source would be the carb float valve not cutting off fuel and it's flooding the cylinder so that gasoline would drain down past the piston rings and into the crankcase. The chance of this happening is slim because you would get a hydraulic lock in the cylinders and also should get starting problems due to flooding. If I were betting on where your problem is, all my money would go on the fuel pump leaking directly into the crankcase.

 

[jbarker855]

This sounds very much like a fixable problem. Your engine is simply flooding. I am not familiar with the particular engine at hand, but Jinman's advice is sound. Check out that fuel pump diaphragm.
-Jay

 

[John Deere 110]

Could Be Your Carb Flooding Out

 

[johann]

Thanks guys,
I will check that out. It would be nice to be able to keep using this machine, it has been really good to me.

 

[WayneB]

I would think it is either the fuel pump or the float in the carb causing the flow of gas to flood out the carb. Then it runs into the oil pan.

My neighbor had the same problem with an old Sears mower and instead of spending more money on the carb he put a shut-off on the gas line leading to it. When he starts the mower he has to wait about 30 seconds for gas to flow into the bowl, then it is off and running. As he finishes mowing he shuts the valve then lets the mower run until it runs all of the gas out of the bowl.

 

[Patches]

Used to be, the needle seat was intergral with the carb body; now it's a little plastic/neoprene?? insert that seats up in the inlet cavity and closes off the inlet side with the needle. If, during your rebuild, you left this piece out, you'll never shut the fuel flow down: just sayin'

 

[jinman]

John Deere 110, WayneB, and Patches: The carb on the Kohler engine has a fuel cutoff solenoid in addition to the fuel float valve. Also, if the carb was flooding enough to fill the crankcase with fuel, the carb would be very wet and probably the air filter would get soaked with fuel. That much fuel on top of the piston, leaking by the rings, would surely also wash all lube off the cylinder walls and piston rings. When/if the tractor started, it would also smoke heavily and belch fuel out the muffler, maybe not start at all due to being flooded.

However, the fuel pump is a pulse type pump that has a hose connected to the crankcase so the pulsed crankcase pressure from the engine running will work on a diaphram to pump fuel only when the engine is running. Below is a picture of such a fuel pump on a Kohler Courage 16 hp engine. You can see there are three hoses: one for fuel in from the tank/filter, one for fuel out to the carb, and another attached to the crankcase (sometimes to the valve cover) to supply the crankcase pressure pulse. That's where I think the problem is and where Johann will find his leaking fuel.

 

[johann]

I was unable to work on the machine this weekend,I am going to head out and look for that valve before I head in to work. Jinman, what would it be doing wrong ? Staying open when off, or is it staying open wile running and passing fuel to valve cover? I should also add that when it was puking out last I took the air filter off to see if it was wet or clogged while it was still running, and it wasn't,but I did get to witness it stalling out and when it did it was sending fuel back into the top of the carb as it was coming to a stop.

Thanks for the help.

 

[jinman]

If the fuel pump is bad, it is an internal leak that is not normal. It's not a case of normal on/off. There is no power going to the fuel pump. The air pressure from inside the engine fluctuates and that is what moves the bladder inside the pump to draw fuel from the tank and send it to the carb. You would see evidence of wet fuel in the air line going to the valve cover. In my picture, I think that's the hose that goes off to the left and down. I'm not sure if yours is the same since this is a late model of Kohler engine that this picture is from.