My son has just bought an ex MOD diesel generator with a Lister-Petter single cylinder electric start engine. When we unloaded it last night I gave the hand crank a couple of turns and it rotated freely with the decompressor engaged, and seemed to hit compression when I disengaged it.
Just tried it again and it is solid whichever position the decompressor is in, can't even rotate it backwards with a screwdriver in the fan.
Pictures can be seen here
Mike
I am away from home from early tomorrow morning so will be unable to reply to answers/questions until Friday.