[Yosemite Sam]

Hold the old and new S/G's side by side to see if they are the same. Check the S/G pulleys to make sure they are the same.

Then check the pulley and basket on the crank to see if it is loose or too far out on the crank. It should be really close to the 9/16" bolt head on the front of the engine that holds the upper S/G Bracket.