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  1. #1
    97 Kawasaki STX 1100
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    pop off pressure checked 97 stx 1100 today - need some advice

    Wondering what you guys have found is the best pop off pressure for these engines

    97 stx 1100 2 stroke with oil injection... Everything is stock.

    Ive been having a issue when sitting idleing then nailing the throttle engine dies. If I baby it I can get it up and going. Once its going it runs awesome. Read many articles about pop off pressure issues with this ski... I pulled the carbs today and yep they were way off. In the 35 to 40 psi range. I pulled the springs and trimmed a couple springs off and got the pressures down to 25 psi as instructed per the article. Wow what a difference. No more engine dieing off idle. But if I nail the gas it sometimes doesnt take off right away may take letting off and re nailing the throttle. Wondering what you guys have found for the best pop off pressure for these engines... Has the 3 cylinder 2 stroke 1100 in it.. 118 psi all 3 cylinders plugs look to be reading even all 3 cylinders and I checked the piston wash today and everything is looking good. By the way I also have a stx 750 and it runs awesome revs right up when I nail the gas. I checked the pop off pressure on that ski today and it was 17psi on both carbs... Any idea what the stock settings on that ski are suppose to be? Dont plan on touching those as they are working great but curious...


  2. #2
    have you tried to richen the low speed circuit ?

  3. #3
    ImpactSportsTV's Avatar
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    I have (2) '97 STX 1100s, both have had your exact same issues - one is perfect now at 17psi pop off, 1 3/4 turn out for the low speed screw (stock is 1 1/4), 7/8 out on high speed screw (stock setting). The other still has a slight lean stumble and I may bump the low speed screws up to 1 7/8 or go up a size on the low speed jets. Both have fresh fuel pump rebuilds and pop off valves. FYI - you don't want to go much lower than 17psi as the pop off valves leak from the engine shaking at idle causing load-up during long no-wake zone idles that is uncontrollable. Hope this helps
    W

  4. #4
    97 Kawasaki STX 1100
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    May 2010
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    Idaho
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    Quote Originally Posted by ImpactSportsTV View Post
    I have (2) '97 STX 1100s, both have had your exact same issues - one is perfect now at 17psi pop off, 1 3/4 turn out for the low speed screw (stock is 1 1/4), 7/8 out on high speed screw (stock setting). The other still has a slight lean stumble and I may bump the low speed screws up to 1 7/8 or go up a size on the low speed jets. Both have fresh fuel pump rebuilds and pop off valves. FYI - you don't want to go much lower than 17psi as the pop off valves leak from the engine shaking at idle causing load-up during long no-wake zone idles that is uncontrollable. Hope this helps
    W
    That is so awesome. This is exactly what im looking for... I have a service manual for the zxi 1100 and assumed the engines were the same. In that manual it stated the Highs are 1 (+ or - 1/4) and highs are 1 1/8 (+ or - 1/4) I was curious after changing your pop off pressure if its normal to get different readings from your plugs... I herd that the engine will run richer once you lower the pop off p
    ressures

  5. #5
    97 Kawasaki STX 1100
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    May 2010
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    Idaho
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    If anyone has a actual manual for the 97 stx 1100 Id love to have one to see if theres differences between the zxi manual and the stx... I have the zxi 1100 in pdf format and a polaris sl750 in pdf format if anyone wants to do some trading.. I can zip any of these files and email them...

  6. #6
    ImpactSportsTV's Avatar
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    Quote Originally Posted by mogyver69 View Post
    If anyone has a actual manual for the 97 stx 1100 Id love to have one to see if theres differences between the zxi manual and the stx...
    I have both... unfortunately in paper. What Kawasaki issues for these skis is the ZXI manual with a "1100STX Service Manual Supplement" to go with it. You are correct for the settings for the ZXI, but the STX supplement has the STX screw settings as: Low speed - 1 1/4 +/- 1/4 turn out. High speed - 7/8 +/- 1/4 turn out. BTW, I just double-checked my "good" ski and my lows are closer to 1 1/2 out rather than 1 3/4, the carb setting are perfect for me at sea level.

  7. #7
    97 Kawasaki STX 1100
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    Idaho
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    Quote Originally Posted by ImpactSportsTV View Post
    I have both... unfortunately in paper. What Kawasaki issues for these skis is the ZXI manual with a "1100STX Service Manual Supplement" to go with it. You are correct for the settings for the ZXI, but the STX supplement has the STX screw settings as: Low speed - 1 1/4 +/- 1/4 turn out. High speed - 7/8 +/- 1/4 turn out. BTW, I just double-checked my "good" ski and my lows are closer to 1 1/2 out rather than 1 3/4, the carb setting are perfect for me at sea level.
    Thank you again...You were very helpful... I did pull the carbs back off and rechecked my pop off after making my new adjustments. I ended up with 24 psi pop off and 1 1/4 on the low and 1 turn on the high speed... Im above sea level here in idaho.. I believe we are at approx 2500 ft. I now have great throttle responce and the ski is running great... Ive pulled my plugs twice now and am fine tuning, but Im pretty happy with 1 turn on the high... Im trying to keep it alittle rich without fouling the plugs... I hit 61 mph on the digital gauge which is pretty good I think... I do know these gauges are never acurate but that is the fastest Ive had this ski since owning it...

  8. #8
    ImpactSportsTV's Avatar
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    Awesome! - glad to be of help
    W

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