In my opinion, one of the best singles ever built. Ball bearings in the lower unit require gear oil. The drive shaft seal is part number SKF-4770 and the prop shaft seal is SKF-5523. It runs on a 24 to1 mix of gas to oil. (⅓ of a pint of oil to each gallon of unleaded gasoline.) The Champion J6C spark plug is set at .030" – breaker points are set at .020". The fuel shut off lever also controls the air vent.