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I have a toro with a kohler 6.75 engine. Oil is being sucked into the carb causing it to surge, blow smoke, surge again. When I clean the oil from the air intake it runs fine. After about 10 minutes it does the same thing. The oil level is within range. Anyone have this problem and have solved it? Thanks

Johno said:

I have a toro with a kohler 6.75 engine. Oil is being sucked into the carb causing it to surge, blow smoke, surge again. When I clean the oil from the air intake it runs fine. After about 10 minutes it does the same thing. The oil level is within range. Anyone have this problem and have solved it? Thanks

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Don't understand why there would be oil in the air intake. Was the mower tipped on its side at some point? If the air filter is filled with oil replace it. If the muffler is also oil soaked you can remove it and heat it with a small propane torch to burn off the excess. Does the mower have good compression? If the oil level is fine, remove the air filter and start the mower up and let it run till the smoke clears then you should be fine.

you have a valve that is stuck open in your carb that is allowing the gas to run strait thought see if your oil stick is over fill and if it smells like gas is in it if so change oil puy on a fuil sut of valve so it wont happen again but you might have to get carb rebuilt at this point but if there is a lot of gas in that oil you can risk doing real damage to that engine

The only way oil can come "upstream" at this speed is through a bad valve seal. In the situation that Thomas describes, the float valve in the carb is stuck open, and gas seeps into the crankcase and thins the oil, but the oil level would be way high and it would smell like gas. The speed at which you say this occurs, it sounds like the valve seal to me.