Drive spacer question
09-30-2008 | 08:35 AM
#11
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From: Frankfort,ill
I was told by riggs marine that built the enginbe the 2in drive spacer was needed because the lower unit would suck air instead of water. ( drive is to high x dim) I will watch my water pressure but was hoping for more top speed. Most fountain are set up for top speed. BUT with 634 hp on dyno sheet the speed is not there with a 28in left hand prop at 5100 it gone 72mph gps.
09-30-2008 | 07:50 PM
#12
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Joined: Sep 2003
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From: Norwalk, Ia
Sounds like you have a multiple setup issues. If you have a 1.3 ratio you have 27% prop slip. If it is a 1.50 you have 20% slip. A good setup is about 8%. I would dump the spacer and start from scratch with setup. Also consider sending in your prop to be checked and labbed. Call Brett at BBlades. They are the best. 920-295-4435
Intiminator prop 71 mph 5200rpm
bravo one 28p 70mph 4750 rpm
bravo one 28 lab 73 mph 4950 rpm
All with 2 inch drive spacer tested with light chop and light load hot 85+ degee day
Boat went 71 with stock hp500 Now 577 bulldog with better exhaust and cam. I will start with the drive and yes I need to check into the prop. Season endding need to get moving.
09-30-2008 | 08:13 PM
#13
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Joined: Jan 2006
Posts: 2,574
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From: Columbus,MI
Your slip is very high and you are using different props, so it is a safe bet the spacer is part of the problem. Try it without one and then try to borrow 1/2" and 1" spacers to test. You are also low on RPM. You should see closer to 5300-5400 with a stock ECM.
10-20-2008 | 06:42 PM
#15
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From: Norwalk, Ia
post results
Took the hit rod yesterday. Cool day 1 to 2 foot chop and windy day. Now with the drive spacer out and with over 100 gallons of gas.
76.7 at 5400rpm.
Beleave it or not the boat came out of the better. The boat had slight chime walk put came out of it and a rooster tail, it never did that before. Maybe with lighter load maybe 1mph or 2
76.7 at 5400rpm.
Beleave it or not the boat came out of the better. The boat had slight chime walk put came out of it and a rooster tail, it never did that before. Maybe with lighter load maybe 1mph or 2
10-20-2008 | 08:44 PM
#18
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From: Bradenton Florida
