OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers SB45 - Kirby to Briggs or ??

Barry, Briggs have two different engine output shaft sizes in the 2 to 3 hp range. Essentially, the 2 hp 60102 has a 5/8" shaft, the 3 hp 9 series engines have a 3/4" shaft, and in between is the 80102 which is probably the engine on your Diplomat. I don't know which size that 8 series engine has. I suggest you add these items to the pictures Deejay has requested:
- full series of numbers stamped on the cooling air cowl of your Briggs engine
- measure the output shaft diameter of your Kirby-Lauson engine where it goes into the clutch
- measure the output shaft diameter of your Briggs engine where it goes into the clutch.

Note we need the smaller diameter of the output shaft at the free end which slips into the bore of the clutch. We don't want the larger diameter of the shaft right up against the engine, where it goes through the oil seal and into the engine.