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  1. #1
    97 Kawasaki STX 1100
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    95 polaris lossing power and fouled plugs

    Someone Help me please. I have a 95 polaris 750 sl. Had it out 2 weeks ago and she ran great 50 mph great take off power etc. Ive replaced the fuel pump with the 3 outlet, new battery and all new fuel lines. Just replaced the float in the fuel tank too.... All before that last trip...

    I just took her out again this week with the family for a couple hrs and all of a sudden loosing top end power stalling at full throttle and fouling all 3 spark plugs. Changed the plugs on the lake with new plugs. Same problem eveytime I give it full throttle tries stalling. I let off the throttle and try babying the throttle on and off and Im able to keep it running... Decided I better take it home before i end up stranded... 10 minute ride back to the dock, on the way back acted up again one time .. I tried easing back into the throttle hit a couple good waves and was able to keep it full throttle the rest of the way home but only ran 40 mph very low power and when I slowed down for waves and tried getting going again felt like it didnt want to get going again but it did and at I was able to get full throttle without stalling... But still not much power... Checked fuel lines no kinks..... ANy ideas????? Still was idling good when I stopped at the dock to load her up and started each time. Volt read 16V so Im guessing the stator is still good.... removed plugs again. All 3 fouled... Im guessing I need to open my fuse box and check for water and check wires... Any Ideas or have any of you had this happen before? Engine rebuilt and jet were rebuilt couple yrs ago... I think I have a electrical problem loading up during full throttle????

    ANy advice please ???


  2. #2

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    post pics of fresh plugs

    do a compresion test

  3. #3
    bowsniper's Avatar
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    hi,sounds like you holed a piston if only going 40.


    What do you mean fouled? if plugs foul, they will not fire at all.the metal in the tip doesnt conduct electricity anymore. try new plugs and a compression test first.

    Whose diagram did you use to install your triple pump? beerdarts? I just did 2 slts yesterday. look under 750 sl carbs on the front page threads. there see if you did it like that.

    Didn't do the carbs huh? new diaphrams in them really help bring it back to life too and you have to keep the carbs clean..

    Change both filters in the lines?

    16 volts? should 14.3-14.6 max. never 16. thats weird,, did you use a multi-meter to check it or the MFD?

    The engine will still run with a hole in a piston as long as it didnt explode or break apart. mine did.

    Is the MFD blinking?

    Was this new battery full charged before using it? what kind of battery did you have?

    Do a cranking voltage test. should be 10.6 or higher while cranking or at least 10. but thats real low for a polaris ski.

    Your voltage regulator could be going haywire if your getting 16 volts. But I'm no expert on electrical!.lol
    Last edited by bowsniper; 06-26-2010 at 11:09 PM.

  4. #4
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by mogyver69
    ...95 Polaris 750 added 3 outlet fuel pump, new fuel lines, battery etc....

    Ski ran great last trip out. all 3 cylinders good compression. 50 mph great top end. Had a great weekend..

    Took it out this week 1 day only. On the lake maybe 2 hrs. Lost top end power 35 mph and started stalling at full throttle.

    Let off the gas and babied it to keep running then floored again same problem.. all plugs fouled. Changed plugs on lake tried again.

    Stalling at full and midrange throttle. Was able to restart each time.

    Volt meter read 16.5V
    so I figure the stator is still charging...

    ... Haven't rechecked compression yet but all 3 plugs looked fouled to me...

    On the way back to the dock to load good 7-10 minute ride I was able to get it to run full throttle without stalling but wouldn't go over 40 mph and when I slowed down I was worried it wouldn't get going back up to speed power was lacking.....

    Man it ran awesome last trip. Haven't touched it other then adding more oil to the oil tank and gas to the gas tank since that last trip...

    Also raised the idle just a little... since it stalled just one time last trip due to very low idle...
    Were the carburetors removed and internally cleaned?

    What settings did you use for the carb adjustment screws?
    Did you adjust the idle speed properly with the hull in the water?

    When it was running well, what was the maximum sustained RPM on the display?
    RPM is more important than displayed speed numbers.

    Check cylinder compression.

    In what way were the spark plugs fouled?
    Brown, Black, oily, wet, dry, bleached white?

    Which spark plugs are you using?

    The voltage shown on the MFD display can be inaccurate. You must check voltage with a multi-meter to properly check charging voltage. Correct charging voltage is right around 14.5 volts. 16 volts, if confirmed on your multi-meter, is too high.

  5. #5
    97 Kawasaki STX 1100
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    Quote Originally Posted by K447 View Post
    Were the carburetors removed and internally cleaned?

    What settings did you use for the carb adjustment screws?
    Did you adjust the idle speed properly with the hull in the water?

    When it was running well, what was the maximum sustained RPM on the display?
    RPM is more important than displayed speed numbers.

    Check cylinder compression.

    In what way were the spark plugs fouled?
    Brown, Black, oily, wet, dry, bleached white?

    Which spark plugs are you using?

    The voltage shown on the MFD display can be inaccurate. You must check voltage with a multi-meter to properly check charging voltage. Correct charging voltage is right around 14.5 volts. 16 volts, if confirmed on your multi-meter, is too high.
    Voltage was checked at lake only with MFD while driving. Carbs were not touched since last trip out when it ran great other then turning the idle screw up alittle while in the water. I turned the idle screw on the left carb on top not the screws you use to sink the carbs on the botton. Plugs were all brown but not wet or oily. Ill hook a volt meter to it tomorrow and check compression. I dont believe its a carb issue since all 3 plugs were foulded rather then just maybe one cyclinder. The fuel pump was installed as stated earlier and the return lines are still stock running thru the rail and the 2 out ports for actual fuel flow from one carb to the next are blocked off with a short fuel line with bolt and a clamp. Each carb is seperatly getting fuel from the pump. It ran great time before last. Ive done nothing new. Sounds like a ignition problem to me like the ignition is breaking down under a load. But This is why Im asking if you guys had any other ideas or if you thought I was on the right track.... I have a spark plug book that shows what indicated fouled, lean or over heated plugs etc. The pic looks exactly like what they are indicating as a fouled plug. Soft, black sooty dry looking deposits indicating a rich air fuel ratio caused by weak igniion, wrong heat range plug, or? Ill let you guys know more tomorrow what I find.

    I cant see a carb problem since the issue is all three cyclinders... Maybe one or two! And it just ran 2 weeks ago perfectly! I think I have a electrical problem....

    Question about oil injection. Can the injectors be removed from the carb and cleaned and or is there a way to clean them? Sometimes It think when it sits I have oil leaking into the carbs. I also noticed the valve at the end of the breather hose for the oil tank drips alittle oil. Could it be pluged or put in up side down?

  6. #6
    97 Kawasaki STX 1100
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    Quote Originally Posted by bowsniper View Post
    hi,sounds like you holed a piston if only going 40.


    What do you mean fouled? if plugs foul, they will not fire at all.the metal in the tip doesnt conduct electricity anymore. try new plugs and a compression test first.

    Whose diagram did you use to install your triple pump? beerdarts? I just did 2 slts yesterday. look under 750 sl carbs on the front page threads. there see if you did it like that.

    Didn't do the carbs huh? new diaphrams in them really help bring it back to life too and keeps the carbs clean..

    Change both filters in the lines?

    16 volts? should 14.3-14.6 max. never 16. thats weird,, did you use a multi-meter to check it or the MFD?

    The engine will still run with a hole in a piston as long as it didnt explode or break apart. mine did.

    Is the MFD blinking?

    Was this new battery full charged before using it? what kind of battery did you have?

    Do a cranking voltage test. should be 10.6 or higher while cranking or at least 10. but thats real low for a polaris ski.

    Your voltage regulator could be going haywire if your getting 16 volts. But I'm no expert on electrical!.lol
    No the MFD was not flashing! Is there a way to check the temperature? Is the sensor just a idiot light that will cause the MFD to flash. I checked all the modes of the mfd and only found voltage and rpm no temperature so I assumed it will flash if its over heating. I noticed a hesitation prier to fuel throttle and then it cut out when I hit full. Once I let off the throttle and eased into it I was able to keep it running then it started acting up again under full throttle. My biggest fear was a lean condition but when I removed the plugs all three cyclinders showed a rich condition....

  7. #7
    97 Kawasaki STX 1100
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    Quote Originally Posted by K447 View Post
    Were the carburetors removed and internally cleaned?

    What settings did you use for the carb adjustment screws?
    Did you adjust the idle speed properly with the hull in the water?

    When it was running well, what was the maximum sustained RPM on the display?
    RPM is more important than displayed speed numbers.

    Check cylinder compression.

    In what way were the spark plugs fouled?
    Brown, Black, oily, wet, dry, bleached white?

    Which spark plugs are you using?

    The voltage shown on the MFD display can be inaccurate. You must check voltage with a multi-meter to properly check charging voltage. Correct charging voltage is right around 14.5 volts. 16 volts, if confirmed on your multi-meter, is too high.
    120 PSI on both front and middle cyclinders. NO compression in the PTO. Pulled it all apart piston is half missing... OUCH!! I dont understand how this still happened to me. The damn thing was running great and had the new fuel 3 outlet fuel pump. Any chance it was already starting to be a issue from previously or do I have another issue I need to address so this doesnt happen again. I need a head for sure and maybe a cyclinder trying to clean the metal stuck to the side of the cyclinder... ANy one got parts for me?

  8. #8
    blegan's Avatar
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    Burning a hole in the P.T.O piston is usually caused bye 1 of 3 things Crank out of index Main seals leaking. Lean fuel cond. You need to figure that out before you put another piston & rings and do the cyl. otherwise youll burn that piston again. This is a common problem on these fujis theres lots of helpful threads on this board
    John zigler for parts. at Rock County Jet Ski

  9. #9
    bowsniper's Avatar
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    See! I told ya you blew a hole in it. the carbs needs to be turned about on all settings about 1/4 turn on everything. then check your wash. That stinks.... sorry to hear. just sounded like it was a hole. loss of power running real good sounds typical.

  10. #10
    bowsniper's Avatar
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    I have a stock cylinderfor ya. you clean hone bore whatever with it, its usuable. 35 shipped.

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