This is a K&B 40 RC Engine. Don't know too much about this engine but it appears that it has barely been used. Super clean and pristine on the outside. Good compression with a nice pop when you turn it over. I believe this is a sleeve bearing model with no rough spots. It comes with an Irvine carb. Comes with spinner prop nut and muffler attached. I guarantee you won't be disappointed with this engine. Serial No. 006829.