I replaced the prop to start my process of elimination. One of the problems that occurs is when I get to 3900-4000 there is a slite slip in the output of forward speed it still is moving but skips.When I run it with the muffs no problem.The new prop is the right make for this P.O.S. 18'9"sportcraft 4.3 OMC.Prop 14.5 x 19 BRAND NEW
