I like using a break in bench, mine started out as a Hudy but I have made some changes. First of all there really is no room for an air cleaner, had to cut the original guard because breaking in an engine without an air cleaner is not really a good idea. With the prop there is alot of air moving so I made a flat piece to block some air after the original one guard broke. Other than that I do a similar method to what you would do if it was in the car. I put a heat cycle on the motor before firing it, 2 heat cycles the first tank then once each tank after that. The nice thing about the bench is it just lets you do other things while you are breaking in a motor. You still need to stay there and monitor temps, it can be difficult to keep enough heat in the engine.

Rex