Rev issue.

WishWish Posts: 6,519 Mega Baller
So periodically when dropping a skier...skier starts cutting out, throttle brought to neutral...there's this rev like the throttle did not return, yet boat is in nutral. Lasts for only a second or two but it's audible. Is that the return spring on the throttle getting old? 1997 SN GT40.

Also, is this the correct impeller?

>>> 11.25..a different kettle of fish. <<<


  • Mark_MatisMark_Matis Posts: 764 Crazy Baller
    A friend's Nautique with PP that I drove for a while would do the same thing - rev up as you pulled the power back to drop the skier. I think that someone here said PP had a version update which fixed that.
  • ScottScottScottScott Posts: 229 Baller
    Your battery is getting low....
  • WishWish Posts: 6,519 Mega Baller
    It is an early version of PP. It does require the occasional loosening of the servo knob to adjust for revs but that only occurs at start ups. Turn boat on, RPMs maybe at 900, turn knob to loosen cable and it goes right back to normal RMPs. I believe PP upgrade back then solved this. But this is when skier is being dropped. Thinkn not the same....maybe
    >>> 11.25..a different kettle of fish. <<<
  • oldjeepoldjeep Posts: 2,374 Mega Baller
    Sounds like a possible vacuum leak.
    Chuck P
    Not a mechanic but I play one at home
  • dvskierdvskier Posts: 69 Baller
    That is the correct impeller for a GT-40 engine.
  • WishWish Posts: 6,519 Mega Baller
    @ScottScott ....huh????
    >>> 11.25..a different kettle of fish. <<<
  • Onside135Onside135 Posts: 369 Solid Baller
    @scottscott...I see what you did.
  • OB1OB1 Posts: 4,212 ★★★Triple Panda Award Recipient ★★★
    What's perfect pass and this servo thingy...
  • HortonHorton Posts: 22,584 Administrator
    @OB1 Google rotary phone

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  • ScottScottScottScott Posts: 229 Baller
    @Wish Just a dumb joke referring to your cell phone screen shot.... Woulda been funnier if the battery was even lower
  • Orlando76Orlando76 Posts: 492 Crazy Baller
    I'm poor and don't have deep pockets so I know what PP is. Sure seems like it's PP doing its thing. My '93 with single line PP does it and so does my old partners '01 GT40 with single line PP. Maybe try skiing one day with handle throttle and see if it still does it?
  • MrJonesMrJones Posts: 1,618 Open or 55K Rated Skier
    Hmmm. I just though it was going to be a Goode bashing thread from the title... ;)
  • DanEDanE Posts: 745 Crazy Baller
    @Wish If PP affects idle at any point your throttle lever and/or PP cable is incorrectly adjusted. Refer to manuals, when you return throttle to neutral/idle there is no way a properly set up PP servo can have input on rpms.
  • BrennanKMNBrennanKMN Posts: 253 Baller
    My GT-40 would do that until I added the second return spring for PP.

    It was because my throttle wouldn't close all the way every time, but would get to neutral. It would sit around 1000 RPM. Once I added the second return spring the throttle would return to idle every time.
  • DWDW Posts: 1,451 Crazy Baller
    @Wish : PP is sensitive to throttle return spring stiffness, the tendency is to want more spring stiffness to return the throttle to idle. Try a new or stiffer spring as noted by Brennan.
  • Mark_MatisMark_Matis Posts: 764 Crazy Baller
    edited June 13
    If that was the problem in this case, @DanE , the "rev" would not "Last(s) for only a second or two but it's audible", but would instead stay up for a longer time. And it would not "rev", but would instead merely not drop all the way to idle rpm. What @wish described is different from that, unless I am misinterpreting his description. And the problem has NOTHING to do with the return spring.

    The suggestion by @Orlando76 is the best way to tell what is causing the problem. Turn off PP and hand drive a pass or two, dropping the skier at the end as you normally would do with PP turned on. If the engine still "revs" the same, then yes indeed, you probably have a return spring problem. If, however, the engine does NOT "rev" when hand driving but does so when you use PP, then the problem is with the PP "software".
  • DanEDanE Posts: 745 Crazy Baller
    @Mark_Matis Yes I agree, my point was if PP cable, brass lever and throttle cable was properly installed and adjusted PP has nothing to do with this as it is completely taken out of the picture in neutral as the throttle cable pushes throttle lever all the way to idle. Most likely another problem, vacuum leak, faulty idle valve, or my favorite- broken diaphragm in the fuel pressure regulator causing random squirts of fuel entering the intake manifold, typically occurs when you bring the throttle towards idle and the intake manifold pressure drops.
    Very easy check, just pull the vacuum hose from the regulator with engine running, the fitting must be completely dry.
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