couple questions about my set up

[donzi-cc]

i have a 20ft sleekcraft tunnel hull and im running a 1997 150hp offshore merc with a redline at 5600 rpms and i have a 22pitch chopper prop and im running 5800rpm at 65mph so i might need a bigger prop and the prop shaft is 4 1/2 inches under the hull im gunna raise the jackplate this week so the prop shaft is about 1-2 inches under the hull and try that ..what do you guys think about that setup ....is there a better prop to run than a chopper and does 1-2 inches under the hull sound right for the prop shaft -thanks john

[David]

You might want to buy a gps, although it might be disappointing.

http://www.rbbi.com/folders/prop/propcalc.htm

On the other hand, you are on the limiter, so more pitch is in order. Probably a 24 with good bow lift. Tempest, Trophy, Chopper would be good places to start.

[donzi-cc]

i already have a hanheld gps thats 65mph on gps it was like 65.3 mph

[David]

Your numbers don't add up, but I'm not about to argue with gps. Try another 2" of pitch with a prop with bow lift. Mazco RE4s are also good.

[Wizard]

Your tach is probably out of whack. Happens all the time. I can't for the life of me imagine a Sleek turning a 22p only to 5600. I also don't think that motor has a limiter! Does the engine sound like it's revving high at WOT? My bet is your closer to 6500. Old tachs do take dumps. Get it tested or get a new one...they are cheap. You really need to know what your rpms are to properly set up the boat.