My #18 arrived Monday, and last night i finally got to play with it. I had it running briefly, but it would not latch the exhaust valve open, so it did not hit/miss. Close inspection found that the piece that holds the roller bearing that operates the rod that opens the exhaust valve was bent in shipping, causing the roller to be at an angle to the cam and also the bearing pin to be loose and finally falling out of its bracket. The governor latching lever is also bent slightly. Once the roller worked loose and fell out, the engine quit running. I have contacted Jin for the replacement parts and am sure he will make it right.
All that said, I love the engine and can't wait to get it up and running again
crazydoug