Force 85 HP (1986) Outboard Motor Parts by All Engine Drill down to the Horsepower, Serial Number Range and Engine Section to get an online inventory of original and aftermarket Force boat parts. We carry Force outboard motor parts for vintage and current model outboards. Choosing the Correct Parts. Your Force serial number is the key to finding the correct parts for your motor. Engine: 1985 Force by Mercury Marine 85 HP (85F5) This 85 horsepower Force by Mercury Marine outboard, manufactured in 1985, is a saltwater model. The engine weight is recorded at 249 lbs. This is a 3 cylinder model. The displacement for the pistons is 72. The bore for this outboard is 3 inches and the stroke is 2 inches. This engine has power steering and a electric-type starter.