Check the NLA fitting and grommet found at the top of the water tube.----If bad you have to find a used one or make one.-----Check water jackets for debris / old impeller bits.------And if there was severe overheat post your compression numbers.
A 15" pitch would be a good starting point.----Is the motor in good shape?----For reference in the future do a compression test.----Post the actual values here.
Do you have all the parts?----The pulleys / cable / spring ?------Have not worked on one in a long time.----Magneto plate should rotate CCW when opening throttle.
Use a piece of glass and emery paper.----Resurface the cylinder head and install with a new gasket.----All 1992 cylinder heads are warped.----You have replaced the water pump impeller ?----Outboards need a new impeller about every 5 years.
Yes they were thirsty.-----The V-4 50 only had 2 big holes for the 2 barrel carburetor.----The 85 HP V-4 in 68 also had a 2 barrel downdraft carburetor.
