I had one of those edgers myself and was going to use the engine, but unfortunately it was in to bad a shape. When we were kids one of my buddies had a Briggs engine with a kick starter on it that came from an old Washing Machine, I believe it was 3/4 HP and he used it on a go-kart. It wasn't as fast as my Minibike with a Power Products 2.5 hp motor but it did the job. What the heck, if it's in good shape give it a shot.
Eagle