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  1. #1

    01 GTS with new engine no throttle response please help

    I have a customers 2001 Seadoo GTS 717 in the shop. Ill start off with letting you guys know I work on PWCs daily and work on them for a living and I am stumped!!! The ski came into the shop because the customer put the wrong spark plugs in the ski and it burnt a hole in the top of the piston.

    Before the customer put the wrong plugs in and blew it up the ski ran great

    I sold the customer a premium SBT engine.

    I installed the engine
    Cleaned the carb and installed a rebuild kit with new fuel pump gaskets, etc
    Blew out the cooling lines to get sand out
    installed new fuel lines and fuel filter
    cleaned the fuel valve
    installed New plugs as well

    The ski starts great and runs great on the hose
    I put it in the water and it will start fine
    run it in the water and it has bad throttle response
    You can floor it from 0 throttle to full and it just gradually will get up to speed
    you can hold it at 1/2 or 1/4 throttle for 1 minute then punch it and it will just gradually get up to speed
    It runs good on top end
    The excelerator pump is working
    I tried new plugs multiple times
    I checked pop off and tried every gram spring
    I tried turning the low speed screw and high speed screw in both directions slightly and it made no difference

    The carb has all seadoo recommended jetting straight from the manual and the exact same thing it had in it before a 75 pilot, a 165 main jet, 1 turn out on low speed screw, 0 on the high, it has a 2.0 seat and the needle is in great shape

    I checked and the fuel pump holds pressure at 10 psi for 10 seconds
    The needle and seat is not leaking any air when under pressure, (no bubbles)
    I tried unplugging the voltage regulator and that makes no difference
    I checked rotary valve timing multiple times and it is correct
    Compression is 145 in both cylinders and I have checked that many times
    The impeller is like new and so is the wear ring
    the engine will turn over freely like it should by hand with the plugs out

    Any ideas or comments will greatly be appreciated!!!!!!


  2. #2
    canuck's Avatar
    Join Date
    May 2006
    The wet left coast.
    Has the impeller been replaced at some point ?

    I had similar problems with my GSI when I first got it, it was a dog to get on plane and had sluggish throttle response off the bottom end. With two people it would not get on plane at all. After about a year of trying and checking different things it turned out the previous owner had installed an impeller that was too aggressive and the 720 did not have the power to get it spinning. New, correct pitch impeller and it was a completely different ski.

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