One of my favorite tools is a piston stop that screws in the glow plug opening . The R/C car guys use them & one of their suppliers will have one . I rebuild a lot of engines & about 1/2 have plier marks on the drive washer . You can cut a piece of leather off a old belt that would go almost around the drive washer & then use a curved jaw pliers. Last would be to cut the prop off & then put a vice grip pliers on the crank shaft (TERRIBLE! I don't believe I said that !) could wrap some tape around it first I guess. DON'T stick any thing in the exhaust port !
Anyhow ,good luck. Max H. [
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