A 1983 model.----What you have is the 9.9 /15 HP adapted to an older midsection , and older 9.5 / 10 HP ??? lower unit.----Also marketed as a 14 HP in later years.----Find the parts at a good dealer.----Take lower unit off.---Post diameter of driveshaft at impeller ( 0.550" ) I think.----Post...