too much prop

[4fun]

i have a 1980 115 evinrude, i have the chance to borrow a 4 blade 21pitch ss prop, off of an 86 150 johnson, is this a bad move or will it not work. the motor runs around 49mph now. according to dash mph gauge. its on a 16'6" performance plus "judge" fg bass boat, with a jackplate that sets about 8" off the transom.

 

[tscott]

Re: too much prop

what are you running right now?? Diameter and pitch wise? Rule of thumb is for every blade you add, go down 1" in pitch.(To keep the same performance)

 

[steelespike]

Re: too much prop

need to know present pitch and rpm.<br /> generally speaking a 4 blade is for power and low end performance.