Recently I purchased an OS Pet .099 from E-Bay. It was a little grungy and locked up frozen from Castor oil residues. I partially disassembled it, cooked it in antifreeze, which softened the Castor and allowed me to extract the steel cylinder and further disassemble.

The prop drive washer's key was damaged apparently by a past attempt to turn the engine over by a propeller mounted while locked up as it was. It spins freely. Fortunately, a gentleman in Canada had NOS parts, so I picked up a drive washer, screw set and gaskets. I also had an NOS muffler I picked up a couple months ago.

It has like new compression, apparently is a low time engine. With a little cleaning and polishing TLC, now I have a decent runner. This is the last iteration of the Pet .099 from the 1960's. It's cylinder liner looks similar to an Enya .09-III cylinder liner, especially how the bypass ports are cut into it.