WHERE IS THE DIFFERENCE ON A STD OR COUNTER ROTATING OUT DRIVE UPPER OR LOWER GEARS?

Question

WHERE IS THE DIFFERENCE ON A STD OR COUNTER ROTATING OUT DRIVE UPPER OR LOWER GEARS?

Answer 1

This is a often misunderstood question, and the answer changes with the different manufacturers.  In some cases it's the engine(s) that change the direction of rotation.  Volvo controls rotation with the upper gears by the cone clutch assembly.  Then They added counter-rotating prop-shafts on the Duoprop drives.  Mercruser uses a little different way to achieve the same result.  I can remember ChrisCraft boats with right and left hand engines, and the velvet drives changed the direction so they had to put an arrow on the coupling so you knew which prop went on which shaft.   I'm sure this clears up your question..Good luck!  

Answer 2

Good one.

The upper gear is on top of the lower gear when it is rotating counterclockwise. When it rotates clockwise, the lower gear is on top of the upper making the upper actually the lower.