A prebuy is OK, bore light in cylinders is OK, but no starting the engine or turning the prop. Doesn't want a stuck valve
If they're saying a bore-scope inspection is okay, the engine has to be rotated so each piston can be moved to the bottom of the stroke.
This has to be done so the bore-scope camera can be positioned inside the cylinder properly to inspect the valves and cylinder walls.
A stuck valve would be the least of anyone's worries.
I know this is not your plane, Wayne and you're simply trying to help someone out which makes it tough on you to answer questions and defend their reasoning but the restrictions in place make no sense........that's not the way planes are typically bought and sold and most everybody knows that.
Jim
