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  1. #1

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    2001 GTi bogging @ 20-30% throttle

    (First off, sorry for a long post, but want to be descriptive)

    I'm new to PWCs, and recently purchase a set of 2001 Seadoos... I knew both needed work, but turned out more than expected... Here's what I did on the GTi at first:

    • Replaced all grey fuel lines with proper black fuel lines, making sure to match up and cut each line sequentially. All clamps replaced with stainless steel. No zip ties.
    • Cleaned fuel petcock thoroughly
    • Full carb teardown/rebuild with brand new gasket kits, making sure to re-use the stock spring to retain pop off pressure. Low speed set to 1 1/4+/-. High speed set to 0, as manual instructs.
    • Cleaned fuel pump - gaskets looked okay
    • New plugs
    Still didn't run right, and would bog down @ 20-30% throttle, but ran 35-40 mph with 2 of us on it... lackluster throttle response above 60%. Was only getting 90PSI compression on both jugs, so decided to pull the heads off, thinking maybe rings were stuck. Oh. My. God. This is what I saw:



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    All I can tell is that whoever did the recent rebuild, they (moronically) put the pistons in backwards, placing the arrows facing AWAY from the exhaust, thus allowing the piston ring gaps to catch on the exhaust port, snapping the rings (and part of the head of the piston) off and smashing against the head. Being as there were no pieces left in the cylinder or crankcase, I can only assume previous owner knew of this, and cleaned/flushed it out, then got running again and sold to me.

    Needless to say, a full top end rebuild was in order. So I had the cylinders bored and honed by a highly recommended local shop. Chamfered the intake and exhaust. Head was also ground/polished to remove damage. Replaced pistons with Platinum WSM (molly coated) ones, making SURE they were installed correctly, and piston rings set on pins. Replaced wrist bearings, as well as all necessary gaskets. Turned over smoothly by hand afterwards.

    Hooked everything back up. Compression went to 130/135psi on just lubricating oil on raw honing. (was told this would improve after break in) Started up just fine once fuel flow was established. Did break in period of <20% throttle with variation for 20 minutes, then let cool down. Then 20 minutes <40% throttle, cool down. 20 minutes of <40% throttle again, then cool down. (will remain below 50% for 10+ hours)

    If you give it 80-90% throttle, (avoiding full throttle just yet) she gets right up out of the water and goes goes goes, but problem is either easing up to the 20-30% range or going 80%, then backing off to 20-30%, it totally boggs, then dies. (just as it did before rebuild) Tried adjusting low speed screw, but opening up makes it worse. Closing it down didn't seem to make a change.

    Looking for advice/direction. Could it be the low speed jet? Being that she seems to get good fuel flow across other ranges, this is all I can think of.

    Thank you very much for looking, and for any guidance you can provide.


  2. #2
    Mtuned's Avatar
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    Pop off pressure

  3. #3

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    OK... So I assume POP off that's too high? (Not 'popping' the needle off the jet soon enough?) Is this from using the stock spring that's rated higher? I will have to find a chart to indicate the colors of the springs and their POP off pressures and see if the ones that came with the kit will work...

    Thanks for your input....

  4. #4
    Mtuned's Avatar
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    Sorry i was at work. hard to reply. Sounds like pop is to high, causing the lean condition.

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