This is a used OS .91 four stroke surpass engine, I do not know how old it is, but it looks like it has been run a lot with a lot of oil. I got it off a plane I recently bought and have recently test run it. It started easily and ran up to full speed with no problems, just over10000rpm on a 12x10 with almost enough thrust to drag the 30lb stand. Type F glow plug and spinner included. It has good compression, and turns freely. I don't know how much these were new, but .72- 1.10 engines are over $300, so...
Will discount $10 if you trade an os e-3030 muffler with the small threads.
Comes with 3 free rx batteries if you want them. They are small (600mah), old and are good for 1-2 flights per charge, the green one is good for about 3.