Picked this engine up at a hobby swap meet/estate table yesterday. From what I have gleaned from the posts here and B&B and US Engines it appears to be a US/Quadra 35cc with points ignition. It appears to never have been run as it is too clean and unmarked as viewed through the port.

The single ring and 1 7/16" bore (measured through the exhaust port) fits the specs given elsewhere on this forum as fitting the 35.

The 6 bolt prop adapter only screws on the front of the crank, which seems incomplete somehow. The muffler is made for the engine as it mates properly to the exhaust port ridges and bolt posts.

I don't need the engine but didn't want it to see it torn down for a go-ped as some fellows were discussing. There is probably a modeler out there who would make good RC use of it or to replace a worn one they already have.

Can anyone shed additional light on the engine?