Oil has a gas smell

[Unregistered]

Last year when I changed my oil during winerization the oil level was above the full mark. I thought initially that I overfilled during top off. I was careful when I changed the oil last Fall and again it is above the full mark. Also, the oil is thinned out and may have a gas smell. I believe that I have an intermittent sticky valve in #1 cylinder as from time to time that spark plug fouls. Is this unburned gas finding it's way into the oil pan over time?

[Don Moyer]

This is quite a serious condition.

You could be getting a small amount of unburned fuel through the first cylinder, but misfiring cylinders seldom produce enough fuel to enter the oil pan to cause a noticeable increase in oil level.

I would check the fuel pump by removing the connection to the carburetor and then hold your finger over the end of the hose or tubing while working the priming lever until it becomes limp (meaning that the diaphragm chamber is fully charged with fuel). Keep holding you finger over the fuel line for a minute or so to see if the pump holds fuel pressure. If the pump does not hold pressure, coupled with the smell of fuel in your oil and the rising level, you may well have a leaky diaphragm.

Regards,

Don