Lawnboy F-engines typically put out about 4 hp, some time a little more. The different configurations effected power like carb, muffler, muffler plate, how the ports were machined in the block, air filter, etc. I was referring to the recoil starter on the top of the lawnboys and Toro/Suzuki. Previous f-engines and older lawnboys had the old side mount starter. I hate the side mount, I adapted a Suzuki starter to a f-engine in about 1986 and then we developed it for the f-engine lawnboy. No kidding.