Motor Speed Issues

[Kevin R]

A buddy and I bought the exact same boat ('05 Crestliner), motor ('04 Johnson 140 4-stroke), trailer, everything (GPS), from Crystal-Pierz this spring. My question is this: My boat will only go 36 mph, even at different trim positions, where as his will go 43-44 mph. We both even have the same prop with a 21 pitch. Crystal thought a lower pitch would make up the difference, and to no avail. I find it odd that there would be a 7-8 mph difference between the two boats. Any thoughts? (The weight has also been relatively the same too.)

[blakjack23]

Are you both getting the same RPM's at WOT? Also, I know on my Tracker that you can mount the engine at different heights and that it will definitely make a different in performance. Are both your engines mounted the same?

Are you both getting your speeds from a GPS or speedo? If speedo, maybe one of them is a little off.

[Fisher Dave]

Weight distribution?

[gofishingtom]

where both motor even though 04 brand new..possibly your buddy has run his more and is broke in more then yours..some 4 strokes take time to break in and pick up the speed...but all other answers are right motors may be on the boats at different heights...

[ricqik]

As they've said, are motor height the same, maybe you're carrying more weight(equipment), try moving weight to the rear most and be a equal as possible side to side, rpms, break-in hrs different, just some thoughts to throw out there for you to check up on. Have you guys ran it side by side?

[Kevin R]

We are both using the GPS for speed. Not sure on the heights of the motors. The weight has been similar, and I believe the hours may be a little different. We are going try them side by side here soon. Thanks for the thoughts.

Kevin