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Thread: POWER PROBLEM

  1. #1
    22ULTRA STEALTH
    I HAVE A 1988 22 ULTRA STEALTH. IT HAS A MARINE POWER SPORTPAC 5.7 LITER 340 HSP ENGINE WITH AN AMERICAN TURBINE AT-309 JET DRIVE.THE PROBLEM I AM HAVING IS NOT ENOUGH POWER.TOP SPEED IS +- 48MPH AND TOP RPM'S IS +- 4400. WHEN I PUNCH THE BOAT OUT OF THE HOLE IT FEELS LIKE IT IS SLIPPING FOR THE FIRST 10 YARDS OR SO, THEN SLOWLY KICKS IN. I AM NOT POSITIVE ON THE IMPELLER SIZE BUT I THINK IT IS AN "A".IT MIGHT JUST BE THAT THE ENGINE IS TOO SMALL AND THE BOAT IS TOO HEAVY.ANY SUGGESTIONS TO GET ME EVEN A LITTLE BIT MORE POWER BOTH OUT OF THE HOLE AND TOP END WOULD BE APPRECIATED.

  2. #2
    1000mhz
    It seems to me that if the boat is slipping the first 10 yards (slippage = cavitation) you either have some crap in the pump ( im sure you already checked) or you have a impeller ware ring clearance issue. Your Ultra should be jumping out of the hole without any slippage at all.
    BTW, If you decide to take your boat to a shop, make sure its NOT ADM boatworks in SoCal. You will end up spending about triple the price there and your boat will be in worse shape then before.
    "Fellow ADM blacklister"

  3. #3
    wrightnow
    Cavitation from a dead stop is not uncommon. One thing you can do is to add an inducer impellar, this sucks water into the pump (loads the pump) and reduces cavitation all together. You can also add a loader grate and have you impeller cut to an AB or B cut. This will increase your top end.

  4. #4
    skeepwerkzaz
    I don't think for are experiencing cavitation. What you may be experiencing is air ingestion. Does any water drip into your bilge from your pump? Also check your suction piece bolts for tightness. These bolts are almost always to loose.
    Skeep

  5. #5
    SUPERCREWJOHN
    Dont you mean a 1998 Ultra Stealth with a 7.4 340 ? I didnt think Ultra made that model in 1988. Heck Ultra 28 was only 20 then..
    seriously though..it sounds like your http://free.***boat.net/ubb/eek.gif impeller http://free.***boat.net/ubb/tongue.gif has had a close encounter with some rocks and thrashed the leading edge..You probably dont have enough motor either, but that wouldnt really cause the problem that you have http://free.***boat.net/ubb/biggrin.gif

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