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Thread: Gt Pro -- New Class For Region 8

  1. #81
    Team Member Smokin' Joe's Avatar
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    Quote Originally Posted by Mark Poole View Post
    Here's my mini boat. If you call 15' mini! Only a few of these were built in Florida and they were center console fishing boats. Never sold well, too small for a fishing boat. I decked it over and made it a sport boat. With me in it and all coast guard stuff, battery, bilge, lights, anchor, etc. it runs 39. Check out the transom pic. It is a 15" motor on a 20" transom. Simple solution, turn jack plate over (I guess it would be called a jack down plate now!) Cav plate is about 2 inches above pad.
    What brand prop, also dia x pitch? I run a 1983 35 on a 350 lb 15' Allison, runs over 41 mph with and into wind (41.5 mph avg., 6050 RPM) but I wouldn't be able to run 20" high, run 19 1/4", 19 1/2" max. Speed is very sensitive to cup (10x14 Stiletto much reworked by me), too much or too little and the speed drops to 37.5 mph.
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  2. #82
    Team Member Smokin' Joe's Avatar
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    Quote Originally Posted by Mark Poole View Post
    What kind of speeds are they getting out of the mono hulls? What mods are allowed?
    46-47 mph@6700RPM with 10x16-17" cleavers, the optimal prop doesn't yet exist. The boats should bereak 50 mph if the right props could be found. I reworked the Yamaha cleavers that some are running, others are running OMC 10x15 SST props and some are running about the same speed.

  3. #83
    Team Member JohnsonM50's Avatar
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    Default 52

    This boat, an H.K. Wetback with a 35 powerhead on an early non-thru hub exhaust 25 lower can break 50.

    Its my pals boat, I gave him the foot. It has the interchangeable 22ci propshaft assembly in it so its easy to adapt speed props. I got a Ron Hill 2 blade righty at 13.5P. The foot is pinned into full time forward & the R-gear has the teeth ground off. [less resistance from mesh & counter-rotation]. The foot has an epoxy cone on it thats carefully split at the seam so it can be serviced. It took some doing but we got it to read 52 gps. The gear ratio is 12:21 so as you could imagine the powerhead was screamin. The Boats fairly heavy at about 480 total & the Rs were about 7200. I told him the motor was at risk running that hi all the time its been goin for a few years & he holds back a little, runs real sweet at 45 to 48.

  4. #84
    Team Member Smokin' Joe's Avatar
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    Quote Originally Posted by JohnsonM50 View Post
    This boat, an H.K. Wetback with a 35 powerhead on an early non-thru hub exhaust 25 lower can break 50.

    Its my pals boat, I gave him the foot. It has the interchangeable 22ci propshaft assembly in it so its easy to adapt speed props. I got a Ron Hill 2 blade righty at 13.5P. The foot is pinned into full time forward & the R-gear has the teeth ground off. [less resistance from mesh & counter-rotation]. The foot has an epoxy cone on it thats carefully split at the seam so it can be serviced. It took some doing but we got it to read 52 gps. The gear ratio is 12:21 so as you could imagine the powerhead was screamin. The Boats fairly heavy at about 480 total & the Rs were about 7200. I told him the motor was at risk running that hi all the time its been goin for a few years & he holds back a little, runs real sweet at 45 to 48.
    Just be sure to run 25:1 Evinrude, Mercury, Castrol or Yamaha 2 stroke oil.

  5. #85
    Team Member JohnsonM50's Avatar
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    Quote Originally Posted by Smokin' Joe View Post
    Just be sure to run 25:1 Evinrude, Mercury, Castrol or Yamaha 2 stroke oil.
    Thanks Joe. I think hes been running 32:1 will advise more.

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    Sam Cullis Mark75H's Avatar
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    Quote Originally Posted by JohnsonM50 View Post
    This boat, an H.K. Wetback with a 35 powerhead on an early non-thru hub exhaust 25 lower can break 50.
    [IMaGe]
    Its my pals boat, I gave him the foot. It has the interchangeable 22ci propshaft assembly in it so its easy to adapt speed props. I got a Ron Hill 2 blade righty at 13.5P. The foot is pinned into full time forward & the R-gear has the teeth ground off. [less resistance from mesh & counter-rotation]. The foot has an epoxy cone on it thats carefully split at the seam so it can be serviced. It took some doing but we got it to read 52 gps. The gear ratio is 12:21 so as you could imagine the powerhead was screamin. The Boats fairly heavy at about 480 total & the Rs were about 7200. I told him the motor was at risk running that hi all the time its been goin for a few years & he holds back a little, runs real sweet at 45 to 48.
    That's the evidence to say we don't need racing lower units to go fast and have fun.
    Since 1925, about 150 different racing outboards have been made.


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    Team Member JohnsonM50's Avatar
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    Quote Originally Posted by Mark75H View Post
    That's the evidence to say we don't need racing lower units to go fast and have fun.
    Yes in the case of a play boat with an underdog lower, part of the fun is workin on it but of course most of its in running. Altho racing lowers are not part of GT Pro [yet ?] the potential for speed out of a 31.8 on one of the applicable boats is 55-60. As is its still a great class & idea, a revival of the 36 class type racing.
    Last edited by JohnsonM50; 01-17-2010 at 03:36 PM. Reason: mistake

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    Administrator Ron Hill's Avatar
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    Default 25:1

    Is 25:1 the right ratio? Or with fixed jets is this the best??? A quart to 5 in 20 to 1. So, what is 25 to 1? A quart to 6.25 gallons?? A quart to a 6 gallon tank???

    In GT PRO can you do anything to the water pick ups??? Seems just filling the top couple of holes what gain some serious speed.

    Never fear, I'm going to the foundry tomorrow and picking up a bunch of props. My GT PRO props will be much improved for 2010.

    The idea that a racing gearcase is needed to race is almost as dumb as thinking you should drive a race boat like my grandfather did!!! AND he drove on his knees. A boat that is raced while on your knees should be called ANTIQUE OUTBOARD RACING. Modern boats have electric starters, power trim and you sit down to drive.

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    I am running a OMC SST 10X15. Needless to say if I raced mine I would be praying for wind and rough water cause I could just hold the hammer down!
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  10. #90
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    Quote Originally Posted by Ron Hill View Post
    Is 25:1 the right ratio? Or with fixed jets is this the best??? A quart to 5 in 20 to 1. So, what is 25 to 1? A quart to 6.25 gallons?? A quart to a 6 gallon tank???

    In GT PRO can you do anything to the water pick ups??? Seems just filling the top couple of holes what gain some serious speed.

    Never fear, I'm going to the foundry tomorrow and picking up a bunch of props. My GT PRO props will be much improved for 2010.

    The idea that a racing gearcase is needed to race is almost as dumb as thinking you should drive a race boat like my grandfather did!!! AND he drove on his knees. A boat that is raced while on your knees should be called ANTIQUE OUTBOARD RACING. Modern boats have electric starters, power trim and you sit down to drive.
    For normal use on the 31.8 the ratio is 50:1 or 2.6 oz per gallon so 25 will be 5.12 ozs per.

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