Thanks for the thoughtful replies guys...much appreciated.

My engine does not have a shim. It does have the 7mm carb.
It does not squeak when turning the prop with the glow plug out, and it does not have much resistance when doing that. However, with the head off and turning the prop, the liner will grab at the top of the stroke and move up about 3mm.

Any ideas on where to get parts (piston/liner/rod)?

Thanks,

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