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  1. #1

    2007 stx 12f Will not rev smoothly and terrible holeshot

    I have a 2007 stx 12f that seems to have been acting strange lately. I think i may possibly have sucked some seaweed or something into the pump but i dont know if this is the cause. When i start the ski in the water or on the trailer, the ski has what i wold describe as a hesitant rev. Its like I squeeze the throttle and it takes a second for the engine to respond. When the ski is in the water it does the same thing and when i gas it at low rpms the ski seems to have no power. Oddly enough, this all seems to go away once i get the rpms up high and ride for some time. The ski has fresh gas in it so it cant be the fuel but maybe the fuel filter? Im going to first change the plugs and see if this fixes the problem and if that's no use then im going to try and remove the pump (I'm going to need some assistance with this ) and see if anythings up cause the ski does have 110 hours . Ive heard about that IMPROS site that rebuilds pumps so maybe that's an option. Any ideas would be greatly appreciated.

  2. #2
    cerebral's Avatar
    Join Date
    Jul 2007
    Virginia, LKA, Colonial Beach
    If you think you sucked something up, something is probably clogged. I would remove some hoses and check for blockage and I would first check the hoses leading to and from the oil cooler on the right side (intake) front, just disconnect them and blow through them after you start it dry a couple time and blow most of the water out the back, don't run it for long just enough to rev once or twice and shoot some water out. Do you have any problems with overheating? I would really doubt you have a pump problem if it does not have problems once up to full speed, pump should be shot or not really, you would be able to tell, and yes I have a 12F .....

    Next check the Entire air intake system, you might have something or alot of water in there, do you see water in the clear plugs at the bottom of the big black air box?


  3. #3


    So I decided to pull my pump to see what what's going on. It was corroded as S**t and was almost impossible to get off. I checked the impeller and it seemed to be okay except for a few minor dings. I decided to get an aftermarket solas so put on since i have the thing off. When I spin the impeller shaft it seems to turn smooth and there doesnt seem to be a problem. A slight worry of mine though is after I put the solas impeller on, the bearing seal at the bottom is moving when i spin the impeller shaft. I don't know if this is okay and I'm starting to get paranoid and am consid3ering just getting new bearings. If this is a problem does anybody know of a good place in new york or new jersey to get the bearings done on my pump? I've heard island racing is good but they never answer their damn phone.

  4. #4
    Here is a video of what I'm talking about.

  5. #5
    Everything is all good now. I swapped my impeller and reinstalled the pump. This didn't fix the hesitation problem, but I changed the spark plugs next and it fixed the problem. The problem now is that my reverse cable doesnt seem to move right, its very hard to pull. Here's a thread on it.

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