Originally Posted by CanadianNorth
Here are my findings: ...
like classic over propping but is would be very hard to get a sailboat that over propped since the propeller diameter is usually limited. Your prop would look pretty unusual, 4 blades, lots of pitch.
I think you probably are over propped but there is also some other stuff going on, possibly as a result of damage caused by the strain the engine has been under since the prop was installed.
This is beyond something you are going to get resolved in a forum, even one with a retired naval architect and designer of many marine drive trains on it. You need to have everything checked from forward flywheel nut to propeller nut.
Get a manual for the engine so you have power curves. Send the prop in for reconditioning. The company should have software to tell you the proper pitch if you can tell them boat waterline length and weight.
It's going to cost some bucks but there are no quick shortcuts here.