600hp Dissapointed top speed and take off!
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600hp Dissapointed top speed and take off!
What's up guys! I have a 1989 Carrera 24ft. With a 502 punched out to 509 est. 600 HP. I did not build the engine so i don't have exact specs of build. The problems I am having are frustrating me. Of course first thing that comes to mind is a prop problem... I have tried 4 different props. The one that works best for me is a Rev4 21p on a bravo 1. Rpms are at 5100 but top speed is only 60mph gps trimmed out. I do live in Utah at an elevation of 4500ft. I would really like to get 65 to 70 out of it. Motor runs like a top so It's not a problem with tuning.
The second problem I am having is prop blowout. When i go to plane out if i gas it at all above 2500 rpm until I plane the prop blows out rpm goes up and boat slows down. I tried a 21p mirage plus but it got worse so i am thinkin maybe a 5 blade would help me out. What's ur guys opinions on it? Thanks in advance!
The second problem I am having is prop blowout. When i go to plane out if i gas it at all above 2500 rpm until I plane the prop blows out rpm goes up and boat slows down. I tried a 21p mirage plus but it got worse so i am thinkin maybe a 5 blade would help me out. What's ur guys opinions on it? Thanks in advance!
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But u are right there is no way I can verify HP output. No engine dynos in Utah either.
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Engine was built before I bought the boat. No the only rev 4 I have tried is the 21p. I am wondering if the outdrive was re geared??
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Prop issue.
I had my 26' boat with 454 Merc. mag. Bravo 1, mirage 23" prop. clocked at 69.3
You should do low/mid 70's with a 502 and try 24-26 props.
502's have enough torque and a 24' boat is light enough.
I had my 26' boat with 454 Merc. mag. Bravo 1, mirage 23" prop. clocked at 69.3
You should do low/mid 70's with a 502 and try 24-26 props.
502's have enough torque and a 24' boat is light enough.
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http://s1186.photobucket.com/albums/...1.jpg&newest=1
Last edited by 348Travis; 07-21-2011 at 10:05 AM.
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I hate to say it but the fact that you're only turning a 21P prop to 5100 tells me you're down on power.
Personally I would try a 23P Rev4 and see what happens. But I'm guessing similar speeds at lower rpms.
Are you getting full timing advance? Jetted correctly for your altitude?
Personally I would try a 23P Rev4 and see what happens. But I'm guessing similar speeds at lower rpms.
Are you getting full timing advance? Jetted correctly for your altitude?