Max hp on a stock 3 point engine mount
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Max hp on a stock 3 point engine mount

  1. #1
    Senior Member Panic Attack's Avatar
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    Default Max hp on a stock 3 point engine mount

    I have a 21 ultra upen bow. Starting to order parts, thinking a big nick aka 598 bbc pump gas deal. The boat does not have a rail kit in it. What do you guys think?

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    Quote Originally Posted by Panic Attack View Post
    I have a 21 ultra upen bow. Starting to order parts, thinking a big nick aka 598 bbc pump gas deal. The boat does not have a rail kit in it. What do you guys think?
    Jeff Johnston had a 496 in a 19' Pioneer, 3 point mount, made a pass at Modesto Res. engine broke loose hitting the passenger in the shoulder, it hit Jeff in the leg...and went through the deck....Jeff doesn't boat anymore

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    Senior Member jetjunky's Avatar
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    I would seriously advise against using that 3 pt. mount. You are going way beyond its intended design.

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    Senior Member jetboatperformance's Avatar
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    Have always thought of three point engine mount setups as production mounts , Three points routinely came on a great deal of new Jet boats in the 70s and 80s with 300 to 400 HP , as you may realize the fronts utilize the automotive mounting pads while the rear simply rests on and clamps on the drive bearing cap , Although Cast aluminum four point mounts are an improvement over three's niether are suitable in my opinion for Larger HP Motor rail kits are stronger and spread the weigh of the engine and load along a greater area of the stringers , they (rail kits) are simple to setup and install

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    Senior Member hihosilver's Avatar
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    I am at 525-550 hp but I modified the floor to support it, still wouldn't go much more
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    Senior Member tigertooth's Avatar
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    Witnessed a zz502 502 h.p. motor driveitself off of a 3 point mount. It wasnt pretty. Disentigrated the driveline as well as te bell housing. Has a rail kit in ot now. 3 points are for stock motors

  9. #7
    kenny nunez
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    Default 3nt point mou

    About 30 years ago a friend was crushed under the deck of his 18' Mandella when the 454 broke loose, of course we think he may have been drunk as he hit a rock jetty at night. I talked to the EMT's and they told me it was one the worst the worst boat fatality they had ever seen.

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    Senior Member Alter Ego's Avatar
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    No sense in risking it. Typically if you have to worry (cuz we are all a little crazy in these boats anyways) then you need to upgrade. Small motors by today's standards are huge compared to when most of the mounting systems were thought up. A good rail kit will decrease stress on the hull, give you options and drastically decrease the risk of one of the aforementioned horror stories!
    2011 Rouse Performance 19'

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    Senior Member jetjunky's Avatar
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    Senior Member Panic Attack's Avatar
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    Quote Originally Posted by jetjunky View Post
    thanks, lots of good info there.

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    Off Road Badass Bonzen's Avatar
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    The term "3 point mount" is referring to the 3 points that the motor is supported? One point on each side of the engine block (BBC uses (3) 3/8" bolts per side) and the driveshaft cover that clamps to the jet drive housing?

    My 94 came stock with that setup but the engine still doesn't make over 400hp even as I have rebuilt it for more power then stock...
    "I'd love to help you out wags, but there is larger issue concerning breast cup sizes on another thread that we have to work thru first. This subject suddenly became a non issue." - GN7

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    Senior Member Bill Oxidean's Avatar
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    I had the engine break loose with 4 point cast mounts because my mechanic used the same rusty ass bolts that came with the boat.
    Not sure why someone would install a new motor and not spend 5 bux or less on some new bolts, but he did and I paid for it. FortunatelyI wasn't injured. You'd be Shocked who on here did that

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    good no one got hurt.that should tell you if you want it done right do it ur self champ.......

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    Senior Member Bill Oxidean's Avatar
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    Quote Originally Posted by nipple head View Post
    good no one got hurt.that should tell you if you want it done right do it ur self champ.......
    You can say THAT again..

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