gas in oil

[stihl-066]

What would cause oil to smell like gas. I have a buddy who has a 351 cleveland and the oil has a faint smell of gas when you pull the dip stick. Doesn't seem to be burning any oil. Or the level of the oil coming up on the dip stick.

 

[dennis112]

What would cause oil to smell like gas. I have a buddy who has a 351 cleveland and the oil has a faint smell of gas when you pull the dip stick. Doesn't seem to be burning any oil. Or the level of the oil coming up on the dip stick.

The fuel is probably draining past the rings by way of the ring gap--a sign of too much fuel.

This is common if the choke sticks, there is too much fuel being added to the cylinder, or when the carb bowls drain (leak) fuel into the intake after shutdown. Can also be caused by not letting the engine warm-up fully before shutdown.

The best course of action is to identify and fix the problem before too much fuel gets into the crankcase and ultimately decrease lubrication.

Definitely he needs to change his oil soon.

 

[BADBOSS]

i'd start with the carb. asap...

 

[rbohm]

i would start at the fuel pump. if the diaphram is punctured, it will pump fuel into the oil pan.

 

[stihl-066]

he plans on pulling his engine to detail is engine compartment so I am sure he will look more into it. When the engine is shutoff I still see a little gas trickling out of the carb. With a little smoke coming up as well.

 

[red65]

Fuel pump. A small puncture in the diaphragm can still allow it to pump enough fuel to run, while letting a fair amount seep right past into the crankcase. If it's enough to raise the oil level, this is almost certainly where it's coming from. Don't run the engine much if you can help it - gasoline-thinned oil doesn't lubricate well!