When you measure the cylinder bore with a *dial bore gauge then measure the diameter if the piston skirt opposite of the wrist pin with michrometers. Subtract the skirt size from the diameter of the cylinder to see if the cylinder needs to be re-bored and honed for the next piston size.
I would add STP or some other thick oil additive that slows oil consumption. If that doesn't reduce smoking and oil consumption, try rebuilding it.
It will fowl your plug more but outside of that just keep oil in it and it will still run a long time. If you tear it down you will have to probably do a lot more work to it than just rings.
Let it smoke. The problem I've found with oil additive or heavier oil is that it clings too much and doesn't drain back into the crankcase fast enough, and tends to smoke more. Just put straight 30 in it and run it. If it burns so much oil that it constantly fouls plugs, you might want to re-ring it.
I have an old lawnmower 1 cylinder Tecumseh engine and I wanted to try a pulley change and see how fast it will go! It smokes a lot but it still starts and runs fine and I know the problem is piston rings since it goes through quite a lot of oil. But is there any point changing them? Can I not just drive a smokey lawnmower that burns oil? Thanks in advance
