I am sort of thinking you have some other issue. Seems that you may be fixated on something that is not the problem. It is very easy to do. Step back and look at every other thing that could make it not run. Change plugs, it can have spark with no compression on it but fail under compression. Larry
You seem to be correct. I replaced the spark plug and the gas at the same time so I don't know which it was. But it is now running. I have, I think 3 gaskets at the bottom and one at the top. I had just enough time to run around the block. It is not running well. but it runs. Will not get up to really good speed... With the head off and the cylinder torqued down, the top outer edge of the piston was maybe a mm or 1.5mm below the top of the cylinder.
Also, the bottom of piston shows just a bit looking through the intake at top of stroke.
Maybe I should remove a gasket?
Also, was running without muffler. What effect does that have?
Thanks all for putting up with me