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  1. #1

    Read my plugs PLEASE....

    I pulled these out of my GP1200 that dropped a cylinder. I didn't have my compression gauge with me at the lake but it felt "by thumb" that all cylinders had fairly equal pressure and the spark was low, about 1/2 the 9mm called for in the manual and it was very weak even then (had to look REALLY close with hand cupped over it to even see it in the shade of the covered dock), so I'm going to have to chase down that issue. However, the carbs were rebuilt last year and I reset jets them in the same position I found the jets in. We finally got to put enough hours on them, for my limited ability, to see much difference. How would ya'll rate them? I think #2 needs more gas. I'd rather have them a little rich and change plugs seasonally than blow up.

    When I got to the dock to look at it, I did a cylinder balance test and pulled plug wires to see which cylinder had the least effect. #1 - engine died almost right away, #2 - basically zero difference in idle, #3 - idle dropped but remained running. What's weird is though is the #2 plug looks pretty healthy but balance test showed #2 being the weakest. I guess spark could have dropped out on #2 and now its running on 1 & 3?




    Should I open up high speed circuit on #2 while going after weak spark issue? Thanks!


  2. #2
    Yamaha artisan Cutlass's Avatar
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    I donít know if weak spark is your issue. Thatís not a common thing we see on these.
    The Thumb-o-meter compression gauge isnít good enough. Do a real compression test and post the results.
    FWIW, my plugs always looked wet so your dry plug concerns me. Besides that we donít really read two stroke plugs like that. We warm up the engine, shut it down, throw brand new plugs in, run WOT, then rip the landyard out to shut the engine off, then read the plugs.
    Reading piston wash is an even better indicator of rich/lean.

  3. #3
    Quote Originally Posted by Cutlass View Post
    I don’t know if weak spark is your issue. ...
    FWIW, my plugs always looked wet so your dry plug concerns me. ...
    Thank you? Thanks for replying! I know the dryness was noted by me too. The "thumb-o-meter" was just to see if there was an obvious massive failure like hole in piston the size of Texas. Unfortunately, the skis are at my son's 2 hrs away. I will have him "rent" a gauge at an auto parts store and get some readings, if you don't mind keeping an eye on my saga.

    I am trying to learn 2 strokes as I have an old school carbed V6 outboard too. I mentioned "piston wash" reading to an outboard mechanic last week and he just kind of shrugged his shoulders like they never messed with that. Do you know why the "art" wouldn't be applicable in both situations?

    I tried doing a "plug chop" last year @ the lake but didn't feel confident in what they were telling me. Plus the stupid things (I have 2) porpoise so stinking bad. This is the 1st time out this year. How long do you run them before they have enough information on the plugs to do a reading?

  4. #4
    Yamaha artisan Cutlass's Avatar
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    I never bothered with reading piston wash or spark plugs myself. I just used a tried and true carb setup recipe I found on this site and it always runs perfectly.
    I also cured my porpoising problem with a scoop style intake grate and a modified ride plate. I put them on at the same time so I canít say for sure which part fixed it but i suspect it was the grate.

  5. #5
    Is the "recipe" in the stickies?

  6. #6
    Yamaha artisan Cutlass's Avatar
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    It might be. Iíve posted my carb settings in several posts. If you canít find it by searching around, Iíll look when I get some time. I canít remember all the details off the top of my head at this moment.

  7. #7
    Plusdome's Avatar
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    Quote Originally Posted by Cutlass View Post
    It might be. I’ve posted my carb settings in several posts. If you can’t find it by searching around, I’ll look when I get some time. I can’t remember all the details off the top of my head at this moment.
    Per Cutlass in another thread -135 mains. 100 pilots. 1.5 N/S and 115 gram spring.
    Highs out 1 1/2 turns. Low out 1 1/4 turns

    Quote Originally Posted by Dentpusher View Post
    Plus the stupid things (I have 2) porpoise so stinking bad.
    8 page thread on porpoising http://greenhulk.net/forums/showthread.php?t=120768

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  9. #8
    Thank you everyone! My son showed up yesterday and I did compression test on both skis. They showed 100-105 on my old tester. I didn't really trust it so I ran to auto parts store today and used one of their "loaners". One ski is 117,115, 113, other was 112,110,112. Not super high but at least no big hole issues. I then turned to testing spark. All of the screw on wire ends ohmed out fine. I grabbed my spark tester and now I have spark, good >9mm spark, white and snappy, on both machines?! Hope this isn't going to be an electrical gremlin. I'm looking toward fuel issues now. I bore scoped the pistons (the machine I have posted pictures of the plugs) and do not see any significant wash. It appears cylinder #2 is attempting to clear some carbon off the edges but the others are fully carboned over.

    I am going to re-plumb the OEM fuel lines, new fuel filters (these are on 2nd year), do the return balance trick with 105 jets and mess with the mixture screws but I have 3 questions.

    1) How long should it take to clear carbon that has accumulated on the pistons to wash off (we probably have 10ish hours of ownership hours on these skis) or will it?
    2) I read nightmare stories about fuel line issues, especially with ethanol fuel. We normally burn NON-ethanol but what/where should I get fuel line that works, preferably ethanol (resistant just in case)?
    3) When I am adjusting a triple carb setup, I make the initial adjustment per manual, then when I make adjustment for idle quality, do you do each carb individually or make very slight adjustments on all 3 then wait for engine to adjust and repeat as necessary? (I tried it individually found it difficult to differentiate any significant changes.)

    Thanks again.
    Last edited by Dentpusher; 07-30-2019 at 03:37 AM.

  10. #9
    If you scroll up you'll see "order performance parts" and can find the fuel line there. There is another forum that links to a different site that does have the fuel line for less... I ordered 25' for my waveraider 1100 and that was more than enough to replace every single fuel line in my ski. Pm me if you need a link as I don't know if sharing competition's links is kosher here

  11. #10
    Let me tell you a way to check running without a guage. warm engine on trailer for a second. then disconnect two wires and just ground plug in them. run engine one one plug and cylinder at a time. may have to choke. If it runs and revs on each cylinder it will run on water. do this on each cylinder for just a few seconds each. #2 looks perfect #1 looks rich as heck and fouled # little rich but really ok Trust me if you fixed as many old polaris blue fuji engines as I have. you can find a non runing carb dead cylinder no fire etc this way quick

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