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  1. #1

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    RPM loss in the dead heat ?

    How many rpm's do you lose from cool temps " like this time of year " to the dead heat of summer ?


  2. #2
    BLACK MAGIC HEADERS hydrojunkie's Avatar
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    Jun 2007
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    new york
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    my conversion ran 8650 and it was on the limiter in 55 degree weather, when i went to sebastian flor it was 93 and i was running about 8350 or so. around 300 or so

  3. #3

    Join Date
    Nov 2006
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    Today air was about 73 and water about 66 , I'am turning 8,240 and saw 8,280 twice. I can feel the rev. limiter so no doubt I'am hitting it.
    I'am running stage one with 1mm added to the 14/19 " never saw the rpm's change once I added 1mm " , Rotax Racing impeller , riva pro sponson's , riva pro block off's , filled holes , vented engine compartment.
    Running high 73's mph a few months ago in colder weather on radar.

    I have a 15/20 on the way but worried about summer heat with it.

  4. #4

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    No wedge , didnt like the feel of it.

  5. #5
    Focker Foggy's Avatar
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    Oct 2007
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    Olathe KS
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    On my 185 GTX, I would lose about 150 - 200 rpms from
    spring to hot summer water and air..
    I would even lose 100-150 from first 10 mins out on lake to
    say a half or full hour later... When I installed the RR thermostat,
    the heat fade on same day riding was gone all the way.

  6. #6
    i made my own 160 deg thermostate get the merc thermostate part # 99155A1 or the serra 18-3555 which replaces the merc i used the one from my ski & found another one cut the other ring holding the center pice in and then i broke the center out of the other with a pair of side cutters be carefull then i took a heat gun and heated the outer houseing that holds the center peace place the merc thermostate in and press the 2 peaces back together untill it snap make sure you dont lose the o-ring but for less than $20 i have a factory looking 160 deg thermostate
    Last edited by yellow jacket; 04-21-2008 at 08:56 AM.

  7. #7
    Robert caldo101's Avatar
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    Sep 2007
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    Jacksonville, Fl.
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    Yeap

    syou will lose 300 rpm +or- but if you get your nozzel machined for rings, then you can change ring to alter your rpm's, with your stock nozzel idealy you want to run a solid 8100, again with changing ring's up or down on size you can change your rpm's accordingly

    Quote Originally Posted by NCRXP View Post
    How many rpm's do you lose from cool temps " like this time of year " to the dead heat of summer ?
    Last edited by caldo101; 04-21-2008 at 09:21 AM. Reason: spell check

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