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  1. #1

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    2003 GTX NA Power and Rpm loss............

    Bought this ski back in the winter with a dropped Intake valve (Guy milled the head to much after a warped head problem and made Valve/piston contact).......$1k.......182 hrs......

    Didnt hurt the block amazingly..... only a piston a new head and a good flushing.....(Valve got wedged in valve seat and didnt really bounce around in the cylinder)

    Fast forward now........

    Max rpm is 6500 consistantly but engine runs smooth at full throttle just low rpm/speed/power
    Idle is a bit rough at 14-1500 in the water
    When cold its hard to keep running until it warms up.....keeps stalling till then.....but still idles rough on trailer


    I'M thinking fuel pump/filter..........Any other ideas??


  2. #2
    Your idle control valve sounds like it isn't bypassing the throttle and screwing with you when it's cold. Simple fix - replace.

    6500rpm I'd check it has the stock prop fitted first, just to make sure you're not chasing your tail. Check oil level, overfill can hang heavy on the engine and drag rpm's down (level should be between two marks NOT up to top one as indicated).

    I assume you have new fuel and plugs, so we can ignore those.

    Try these things, then report back, fuel pump could play a part, even 1 or more coil pack failure could also be your problem. Take it a step at a time. You could always borrow the parts from your other ski to test. Coil pack swap is a 30 second job.

  3. #3

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    Quote Originally Posted by tornado34 View Post
    Your idle control valve sounds like it isn't bypassing the throttle and screwing with you when it's cold. Simple fix - replace.

    6500rpm I'd check it has the stock prop fitted first, just to make sure you're not chasing your tail. Check oil level, overfill can hang heavy on the engine and drag rpm's down (level should be between two marks NOT up to top one as indicated).

    I assume you have new fuel and plugs, so we can ignore those.

    Try these things, then report back, fuel pump could play a part, even 1 or more coil pack failure could also be your problem. Take it a step at a time. You could always borrow the parts from your other ski to test. Coil pack swap is a 30 second job.
    Oil is perfect......already swapped coils.......plugs are new......Pretty sure the prop is stock.....guy I got it from was pretty straight forward with me and wasn't into modding it......he just liked to ride with his wife once in a while......he was an older guy so I couldn't see any advantage in him lieing to me about the prop with an obvious dropped valve sitting in the engine .......he said he checked it with a Gps a few times and ran 53-54 on glass at around 7400 RPM.

  4. #4
    Has it run above 6500 since it's been re-built?

    If not, then it could be a mechanical related problem (which could be many things with the internals). Of course it could be fuel pump related, but I'm leaning more towards internals.

  5. #5

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    Quote Originally Posted by tornado34 View Post
    Has it run above 6500 since it's been re-built?

    If not, then it could be a mechanical related problem (which could be many things with the internals). Of course it could be fuel pump related, but I'm leaning more towards internals.
    It has an COMPLETE 06 head (meaning nothing from the 03 head was used) with the restrictor removed from the block but i know the timing is setup correct.....I only had to change the one piston....I never removed the other 2 pistons......only rod caps to replace bearings.....dont see how anything mechanical could cause that.......oil pressure is 45 psi at idle once warmed up...about 85 cold

  6. #6
    Vern's Avatar
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    Oil pressure sounds good, do a compression check and report back. Also not a bad idea to pull the fuel pump and check the condition and replace the filters, and/or install a fuel pressure gauge too. Rough idle AND low rpm can indicate cam timing being off ... compression numbers will help to indicate if cam timing is OK. After removing head and seeing your two symptoms can be cam timing off.

  7. #7

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    Looks like it was the fuel filters

    Click image for larger version. 

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    Ski starts right up now and idles much cleaner.....havent taken it out yet but just the idle alone is a vast improvement

    by the way all three cylinders are 180 psi on the compression test.

  8. #8
    Quote Originally Posted by 4skis View Post
    Looks like it was the fuel filters

    Click image for larger version. 

Name:	20150630_192512.jpg 
Views:	47 
Size:	71.4 KB 
ID:	363993

    Ski starts right up now and idles much cleaner.....havent taken it out yet but just the idle alone is a vast improvement

    by the way all three cylinders are 180 psi on the compression test.
    Let's hope this is the fix. Please update when you've water tested. Cheers

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  10. #9
    kensmith's Avatar
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    Quote Originally Posted by tornado34 View Post
    Quote Originally Posted by 4skis View Post
    Looks like it was the fuel filters

    Click image for larger version. 

Name:	20150630_192512.jpg 
Views:	47 
Size:	71.4 KB 
ID:	363993

    Ski starts right up now and idles much cleaner.....havent taken it out yet but just the idle alone is a vast improvement

    by the way all three cylinders are 180 psi on the compression test.
    Let's hope this is the fix. Please update when you've water tested. Cheers
    Good to know keep us posted

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