A couple of years ago I bought the Craftsman M320, which has the "No need to change oil" engine from Briggs & Stratton. At first I carefully checked the oil, and since it never seemed to use any, I thought things were fine. They weren't. When I noticed some blue smoke coming from the exhaust, I shut it off and checked the oil - more than enough. Why? since I never added any oil. Well, I decided to extract the oil and add new. I removed slightly over 20oz of oil from an engine that only takes 15oz. Apparently, there has been some gas that is blowing by the rings. (I have St. Augustine grass and the mower works hard.) My suggestion to anyone that has this mower, check the oil level and if it slightly over the mark, change it.
#2
StarTech
Probably not blowing gas past the rings but has a carburetor float valve leaking instead.
