Chosen Solution
When I start my mower, it runs for 5 seconds with tons of smoke and oil coming out of the muffler. I can immediately start it again with the same results over and over. The fuel lines are clean. I took apart the carb and cleaned it with carb cleaner but it was already pretty clean. I had a similar problem in the spring and I think it was water in the gas. At the time, I drained it all then and added new gas. It ran fine two weeks ago. The gas tank was essentially empty when I went to start it this week and I think it may be losing gas between mows. I got brand new gas to put in. Then this happened. I haven’t tipped it on its side or anything. Note: after letting it sit for an hour, it started and ran for a minute or two before dying. After that, it went back to dying after 5 seconds. What could it be?
You have either a stuck oil ring or damaged piston. You have oil getting into the combustion chamber. You are going to have to pull the heads off of the mower. It has something wrong internally. There is another possibility. Is the oil over filled?
