Propping a 27 Fountain
#11
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Joined: Jan 2001
Posts: 710
Likes: 1
From: Cincinnati, OH
I have same boat as you but 2002.. out of the factory was with a Bravo 1 24P 4 blades doing 65 mph half tank... now running Bravo 1 26P 4 blades.. 68-70mph with full tank and 3-4 persons onbord @ 4950 rpm.. i'm very surprised to see 5200 rpm with your 28P.. it must take forever to jump out of the hole.
#16
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Joined: Jul 2013
Posts: 54
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From: Lake St. Clair ,MI
I have an 04 27 with the same set up. I run a 30 bravo and turn 5000 rpm with 2 on board light fuel at 69mph. Tried a 28 and was all over the limiter. Next step I am gonna try a p5x hydro but I think 70 will be the max for this combo. 30 bravo cruises way better than the 28 IMO.
Matt
Matt
#18
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Joined: Jan 2004
Posts: 2,777
Likes: 12
From: San Diego, California
You're right there. If you install a simple SmartCraft Gauge or put a computer on it you will see that your tach is slightly off. 5150 is the stock limiter in the 555. You have a 1.65 drive. With a light load of fuel and by yourself, you will bump the limiter a little if trimmed at about 5 or just barely, barely over 5 (say 5.1 or 5.2).
Jason did a bunch of prop and drive testing with that boat (SDFever).
Jason did a bunch of prop and drive testing with that boat (SDFever).
#19
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Joined: Jan 2004
Posts: 2,777
Likes: 12
From: San Diego, California
The tooth count difference on the gears from 1.5 to 1.65 is 2. Consequently, two teeth are equal to two inches in pitch if you're talking stock bravo 4 blade props. ..And those are about .7 less than stamped size. a 28 is really about 27.3 "real" inches.
#20
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Joined: Jul 2013
Posts: 54
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From: Lake St. Clair ,MI
I wonder why some have 28 pitch props with the 496 and some have 30? Same drive ratio and I would imagine same x dimension. I tried a 28 bravo and was on the limiter at 3/4 throttle. I can easily spin 5100 with my 30 but my speed seems right in line with everyone else. Oh well I guess like everyone says leave good enough alone but sometimes we can't!!
Matt
Matt



