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  1. #1

    2006 STX-12f low power

    2006 STX-12F does not accelerate past 4000 rpm and only goes 10 mph. I have transferred between FPO and SLO with no difference. Ski will reach 7000 rpm while on hose. I have checked spark plugs and have good fuel. I will check fuel filter this weekend. Ski ran fine last time out. Any help would be appreciated.

  2. #2
    Check compression of all 4 cylinders and post.
    That's the first step.

  3. #3
    Compression 160# on all cylinders

  4. #4
    Changed plugs, fuel filter and oil. Ski reaches 3250 rpm on water but runs at 7000 rpm on hose. Also replaced water temp sensor. It appears that ski is in limp mode while in water. Help anyone?

  5. #5
    What lead up to this problem. When was it last working fine and how or when did it stop. How many hours? any water infiltration? RPM does not tell the whole story it's easy to reach high rpm out of the water there is no load.

    It could be a suffication issue in that you have an exhaust leak. Take the seat off and run it in the water. If that allows you to run normal or near normal then start looking for the leak.

    It could be a fuel venting issue. If the your fuel tank vent line is restricted that would prohibit you from getting full speed and power.

  6. #6
    Ran fine until this problem showed up. Ski has ~40 hrs on it. Ran on water hose and did not see or here exhaust leak. SLO and FPO mode work while on hose. Will check fuel tank vent.

  7. #7
    Fuel vent working fine.

  8. #8
    I have similar problem on '97 900Zxi. Runs fine, RPM responsive on hose. In the water full throttle only getting 5000 RPM and 40mph when a couple weeks ago it was getting 50. Then it will get progressively worse.

    First symptom was going along at 50mph 2 weeks ago and it just died. Would restart and bog down and limp back to the trailer. Suspected electrical problem. Tore down box found a very corroded voltage regulator and replaced that and reassembled (along with some broken plastic joints which had allowed the water in there in the first place.

    Everything back together, electrically seems great. I did notice that the little clamp for the oil into the carb was disconnected today and reconnected. Haven't checked compression yet, plan on doing that today or tomorrow.

  9. #9
    OK, Ran fine on the hose. Took it to the lake, immediately start was a little boggy, and then unresponsive throttle. Full throttle barely managed 4000RPM. Tried starting again and really had to work at it. Came back home, at first start was a little slow, but pulled choke and then engine starts and very responsive throttle to 7000 RPM. Engine sounds great when on the hose.

    I did try turning the water on the hose first BEFORE starting engine and got similar results (boggy start, hard to start, unresponsive throttle). Turned hose off, started after 2 starts fine and then added water and responsive throttle to 7000 RPM again.

    Suggestions? Local marina lost their jetski tech so I am on my own (and I'm not a mechanic!)

  10. #10
    Well, news isn't good. Compression on 3rd cylinder (the one where the oil line came off because of the POS clamp) gets 0 compression. $%^&!

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