Quest for 80's
#33
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With the prop slip calculator my slip for the 28p is around 17-18 percent. I mean it hardly sounds like the motors working to get to the rev limiter. The motor dynoed 735hp, will a 30p help this or will I have the same problem getting on plane? Really don't want to jump up to a 5 blade.
#34
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From: Fredericksburg, Va
boat should be dead in the 80's...even before, need to get rev limiter up...need to turn 5600-5800, make sure running LH prop, either 28 or 30 hydromotive should be the trick, make sure that you are getting boost, if not take off flame arrester and run without to see if that changes...something not right with your setup...
#35
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From: Newark, DE
Not sure if I missed it somewhere but where did the motor make peak power at? With 735hp in a stepped hull 29 fever set up correctly you should be hitting the 90's or damn near close to it. Its kinda weird that the hydro is blowing out, fountains pre 2000's love hydro's, some people do experience a negatives here and there getting up on plane, but nothing crazy that I have heard. With 735hp and a 5 blade probably is not the best idea, specially with a LH rotation drive (if you are LH rotation you should look into getting a billet top cap), and really if you have a stock x dimension a 5 blade shouldn't be necessary. I have a 95 27 stepped hull fever and I am right around 4.5" below the bottom on prop center line. At 77mph you are way off the mark of what that boat should run with that power.
Last edited by ealesh33; 03-20-2015 at 10:00 AM.
#36
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From: Newark, DE
Well took the boat out for the first time today with new motor. Ran 77mph with a bravo 28p prop at 5400rpms (it was sitting on the rev limiter). Swapped out with a 29p hydro motive prop and couldn't get on plane. Kept blowing the prop out as soon as it would go to roll over. So kinda looking on advice on where to go to next? I heard hydro props run mor pitch then a bravo prop. So I was thinking about maybe trying a 30p bravo prop. We did have 6ppl on board, full cooler, and full of fuel though. So am I headed in the right direction with a 30p bravo? Or should I look at a 27 or 28 hydro?
#37
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Joined: Jul 2004
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From: chicago
Original motors power was unknown. New engines he ran 77 banging the limiter. Not 77 mph max.
I've seen it many times when a prop simply has the cupping washed away, or a poor repair removed much of it. I've seen high x SSM boats not plane with 18" 5 blades, but lay right over with 17" 4 blades. Its not always x dimension or blade count.
Another thing to keep in mind. Sea level, salt water can be a lot faster than a freshwater boat in a bit of altitude.
Is there a dyno sheet to see where this engine would be happy at rpm wise ?
I've seen it many times when a prop simply has the cupping washed away, or a poor repair removed much of it. I've seen high x SSM boats not plane with 18" 5 blades, but lay right over with 17" 4 blades. Its not always x dimension or blade count.
Another thing to keep in mind. Sea level, salt water can be a lot faster than a freshwater boat in a bit of altitude.
Is there a dyno sheet to see where this engine would be happy at rpm wise ?
#38
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From: Newark, DE
With the prop slip calculator my slip for the 28p is around 17-18 percent. I mean it hardly sounds like the motors working to get to the rev limiter. The motor dynoed 735hp, will a 30p help this or will I have the same problem getting on plane? Really don't want to jump up to a 5 blade.
Last edited by ealesh33; 03-20-2015 at 10:18 AM.



