Small Engines (Lawn Mowers, etc.): Crakcase play, briggs straton, vertical shaft

Question
I have a Briggs & straton 16 hp vanguard vertical shaft engine model 303777 type0411-01. The flywheel is hitting (rubbing) on the mounting screws of the alternator and oil is leaking from the oil seal on the magnito side.  The crank will move up and down about an 1/8 of an inch. I removed the sump or crankcase cover. There is a small ridge on the cover next to the crankshaft where the timing gear on the crank comes in contact with the cover. I ,m assuming this is a wear spot leaving the ridge causing my problems. Shuold this surface be flat? the ridge is about 1/16". Are shims or a new cover a solution to this problem? The engine is 17 years old and still runs good

Answer
Hi Brent
Yes the surface should be flat. Also check that the flywheel key is in good shape and installed properly and that there are no washers missing. I would also replace the top seal and bottom seal while it is torn down. I haven't heard of shims being used. If the area appears to be badly worn, then replace the cover. It is not uncommon for an engine that old to have pieces worn and play in them but it can be corrected. Hope this helps.