umm interesting, ok
I have taken the spark plug out and your right there is little resistance agreed
ok the pull starter its zenoah original of the 320 the pawl is metal and a wire cable which isn't bent or twisted anyway
and smooth as silk , and always been told compression is high, but I don't believe this is a compression issue,
I'm not saying the crank is FUBAR just enough to cause a variation in rotation to cause a problem
note to add, a year ago I had drill starter KILLER RC which was slightly damaged when I put drill in
and tried turning over there was a clunk at every 360 rotation I tried that for about 10 rotations
and realised something was wrong and this "compression" has been there every since now at that time it obviously caused
an issue not for engine run, runs sweet as I said, just the initial issue, which I believe isn't compression
sorry to go bout this a real head scratcher
ps how could it possibly be pullstart related with much respect