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  1. #1
    97 Kawasaki STX 1100
    Join Date
    May 2010
    Location
    Idaho
    Posts
    163

    please help - will someone please look at my spark plugs and tell me what you see?

    Hey guys. Just replaced my rear Pto piston and rings. Took it out today and ran it for a good 2 hrs. Took it home and pulled the plugs. I have a PV100 fiberoptic telescope so I looked at the piston wash and finally Ive got some wash in my rear pto. Looks alittle leaner then my center and mag. But I have a nice black oiled piston with clean areas around the intake ports on the piston.I have my carbs adjusted to 1 turn front , 1/2 turn center but I had my rear PTO 1 1/4 turns because of a previous issue with no wash on that rear piston. I did have low compression in that rear cyl before 100 psi and the cylinder was out of round so I thought I may of had some blow bye that may of contributed to my problems. I replaced the cylinder STD bore and lightly honed it , replaced the piston (new) and rings and just to be safe went ahead and ran that rear cylinder carb rich 1 1/4 turns rather then 3/4 just in case I did have another issue. I think Im still running lean. My front plugs were wet but that rear plug is dry. I did perform another compression check. My front and center are 125 psi and my rear Pto is now 120 psi and Im guessing once the rings finish seating it will come up alittle more.
    The motor was just out last yr and the case was split and all the internal seals were replaced. All of them! WHat do you guys think? Heres some pics of the plugs.
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  2. #2
    97 Kawasaki STX 1100
    Join Date
    May 2010
    Location
    Idaho
    Posts
    163
    Just a note: I just pulled my plugs in my other jet ski to compare and noticed those plugs were all fouled looking too and so now im wondering if that one fouled looking plug isnt just that fouled. We did drive thru a very long stretch of a 5 mile hr stretch just before pulling the skies out and I know 2 stroke are known for fouling plugs at idle. My piston wash wasnt to far off on that cylinder but again I did have the carb adjustment set rich... hmm

  3. #3
    WFO 4 LIFE nitrosportman's Avatar
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    May 2011
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    Temple, TX
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    235
    plug reading must be done at full throttle when at full throttle kill the motor then read the plugs any running after that will mess up your readings

  4. #4
    Polarisitis loonatik's Avatar
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    May 2010
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    Quote Originally Posted by nitrosportman View Post
    plug reading must be done at full throttle when at full throttle kill the motor then read the plugs any running after that will mess up your readings
    +1

    Warm up the engine
    Install brand new plugs
    WOT run 100 yards
    Kill engine without letting off throttle
    Now you can read the plugs

    Oh BTW, be sure to take plug wrench with you

  5. #5
    WFO 4 LIFE nitrosportman's Avatar
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    May 2011
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    235
    take some fresh plugs with you too it makes reading them easier

  6. #6
    97 Kawasaki STX 1100
    Join Date
    May 2010
    Location
    Idaho
    Posts
    163
    Quote Originally Posted by nitrosportman View Post
    take some fresh plugs with you too it makes reading them easier
    Hey guys. Went back out to lake today and did some full throttle passes as recomended. Noticed after full throttling when Id let off the gas and get back into it it was bogging down so I went back to shore and adjusted that rear pto cylinder down leaner. i Had the adjust really rich to begin with 1 1/2 turns so I turned it to 1 1/4 the bog got better and the rpm too. So I went back again and turned it to 1 turn still it got better so finally I set it to 7/8 turn and it was great good responce. (94 sl750 recomended adjustment)So now I checked the plug and it was fouled so I replaced it with a new one and did some full throttle passes and cruised the lake for a bit. A good hr driving around and jumping wakes and playing but no Idling. Pulled it from the water and pulled the plugs and to my surprise it was perfect. Matched my other 2 plugs... Now I have another problem! But first wanted to let you guys know after I got home this evening I pulled the cylinder heads from all 3 cylinders and took some pics. Finally I have piston wash on that PTO cylinder and its looking much better......Before you judge the wash though know that I am running 40 to 1 mix in the oil due to the new piston and rings and also my ski still runs a oil pump so its getting lots of oil. Ive included one picture showing what the center cylinder looked like before we added the oil to the gas to show it was running good before. The first pic is the mag the second is the Pto and the 3rd is the center. The forth is the center before oil was added to the gas... no other adjustments were made to that cylinder....
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  7. #7
    97 Kawasaki STX 1100
    Join Date
    May 2010
    Location
    Idaho
    Posts
    163
    Now for my new problem. The ski did not want to take off. I had to sit there and throttle the gas and play and play to get it to go. Once I got it going it ran great mid thru full throttle but as soon as Id stop again it didnt want to go again. It would stall when Id give it gas and was even more difficult when it was cold... Later when I got home I was going to take my carbs off and inspect them I noticed when I pulled the return line off my carbs gas was sucking into the hose. I removed my gas cap and a serious suckshun from the tank was herd like the vent isnt working on the gas tank. I was thinking that maybe is my problem... Is there a vent on the tank on these or a turn over check ball I should be checking. My other ski I pulled the cap from and it didnt have this same condition.

  8. #8

    Join Date
    Aug 2006
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    Iowa
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    Wash looks really good to me. And yes, their should be a vent line with two check valves. One for positive pressure release, and one for negative pressure. If your negative pressure valve is bad or installed backwards, you can starve the engine of fuel after prolonged riding due to a vacuum in the fuel cell. Much easier to test or replace them often, rather than diagnosing when you have a problem. (unless you do test them, it's hard to duplicate your fuel issue before it's too late).

  9. #9

    Join Date
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    Iowa
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    Pic 2 & 3, both look ok, but a little more fuel won't hurt and should be plenty safe.

  10. #10
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    Oct 2006
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    Cleveland OH
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    I agree.

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