Inspect and clean.

Received a Tower .75 engine last week. The engine had a bind and didn’t turn through top dead center. Disassembled the engine and it appeared to have lapping compound on the piston. Burs were also found the on the sleeve at the top.

Although not a lot of trouble to fix the engine should not be run without inspection and cleaning and in this case fitting the piston.

One might guess that lapping compound was to assist in quicker break in.

Bill