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  1. #1

    Plug colors to tell if its lean or rich?

    Hello everyone.. I'm new here and just wanted to say thanks to all the questions and answers this site is very helpful..
    I have a 98 gtx limited and changed the lines cleaned the raves and rebuilt the carbs.. I was wondering how to tell how it's running(rich or lean}.. I know all the details like holding throttle at 1/4 for 10 minutes with the engine warm and new plugs installed then looking at the color then 1/8 adjustments. Tighten for lean and loosen for more rich.But I'm finding it hard to tell by the color of my plugs.
    there kinda brownish on the electrode and kinda wet black on the threads.
    I also found info of tuning a carb by finding the highest rpm range while adjusting the low speed screws not sure if this applies and if so can i adjust one screw at a time or both low speed screws at once.
    any pictures of what to look for would be great.. And also any tips on adjusting the high speed screws? There very hard to reach.
    I don't have any proper testing tools for pop off and my air box is stock. Aswell as everything else but the grate.
    Last edited by Port credit GTXL; 05-21-2013 at 08:01 PM.


  2. #2
    flyin' the friendly skies airbornexp's Avatar
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    Quote Originally Posted by Port credit GTXL View Post
    Hello everyone.. I'm new here and just wanted to say thanks to all the questions and answers this site is very helpful..
    I have a 98 gtx limited and changed the lines cleaned the raves and rebuilt the carbs.. I was wondering how to tell how it's running(rich or lean}.. I know all the details like holding throttle at 1/4 for 10 minutes with the engine warm and new plugs installed then looking at the color then 1/8 adjustments. Tighten for lean and loosen for more rich.But I'm finding it hard to tell by the color of my plugs.
    there kinda brownish on the electrode and kinda wet black on the threads.
    I also found info of tuning a carb by finding the highest rpm range while adjusting the low speed screws not sure if this applies and if so can i adjust one screw at a time or both low speed screws at once.
    any pictures of what to look for would be great.. And also any tips on adjusting the high speed screws? There very hard to reach.
    I don't have any proper testing tools for pop off and my air box is stock. Aswell as everything else but the grate.
    running rich your plugs will be sooty black. lean would be a whiteish color almost burnt and just right is a dry chocolate brown color. don't worry about the threads just watch the electrode and the porcelain end above it. to do this correctly you have to do a "plug chop" take the ski out on the water and run it wide open. once you reach top RPM, pull the chord and kill it without taking your hand off the throttle. pop the seat and pull the plugs before you restart and see what the color of the plugs are. adjust from there. Yes, the screws are a PIA but that's just the joy of working on these old bitches. it will take a little time to do it right but it will be correct and you wont be "that guy" at the boat ramp with a busted ski holding up the line.

  3. #3
    Quote Originally Posted by airbornexp View Post
    Quote Originally Posted by Port credit GTXL View Post
    Hello everyone.. I'm new here and just wanted to say thanks to all the questions and answers this site is very helpful..
    I have a 98 gtx limited and changed the lines cleaned the raves and rebuilt the carbs.. I was wondering how to tell how it's running(rich or lean}.. I know all the details like holding throttle at 1/4 for 10 minutes with the engine warm and new plugs installed then looking at the color then 1/8 adjustments. Tighten for lean and loosen for more rich.But I'm finding it hard to tell by the color of my plugs.
    there kinda brownish on the electrode and kinda wet black on the threads.
    I also found info of tuning a carb by finding the highest rpm range while adjusting the low speed screws not sure if this applies and if so can i adjust one screw at a time or both low speed screws at once.
    any pictures of what to look for would be great.. And also any tips on adjusting the high speed screws? There very hard to reach.
    I don't have any proper testing tools for pop off and my air box is stock. Aswell as everything else but the grate.
    running rich your plugs will be sooty black. lean would be a whiteish color almost burnt and just right is a dry chocolate brown color. don't worry about the threads just watch the electrode and the porcelain end above it. to do this correctly you have to do a "plug chop" take the ski out on the water and run it wide open. once you reach top RPM, pull the chord and kill it without taking your hand off the throttle. pop the seat and pull the plugs before you restart and see what the color of the plugs are. adjust from there. Yes, the screws are a PIA but that's just the joy of working on these old bitches. it will take a little time to do it right but it will be correct and you wont be "that guy" at the boat ramp with a busted ski holding up the line.
    and its the same thing for the low speed with 1/4 throttle and then pull the key right?
    Is there any other methods worth mentioning or is this the best most accurate method?
    also have you heard anything of the other method I was talking about? While running adjust until you idel reaches peak rpms?

  4. #4
    flyin' the friendly skies airbornexp's Avatar
    Join Date
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    Location
    Mahomet, Il. USA
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    Quote Originally Posted by Port credit GTXL View Post
    Quote Originally Posted by airbornexp View Post
    Quote Originally Posted by Port credit GTXL View Post
    Hello everyone.. I'm new here and just wanted to say thanks to all the questions and answers this site is very helpful..
    I have a 98 gtx limited and changed the lines cleaned the raves and rebuilt the carbs.. I was wondering how to tell how it's running(rich or lean}.. I know all the details like holding throttle at 1/4 for 10 minutes with the engine warm and new plugs installed then looking at the color then 1/8 adjustments. Tighten for lean and loosen for more rich.But I'm finding it hard to tell by the color of my plugs.
    there kinda brownish on the electrode and kinda wet black on the threads.
    I also found info of tuning a carb by finding the highest rpm range while adjusting the low speed screws not sure if this applies and if so can i adjust one screw at a time or both low speed screws at once.
    any pictures of what to look for would be great.. And also any tips on adjusting the high speed screws? There very hard to reach.
    I don't have any proper testing tools for pop off and my air box is stock. Aswell as everything else but the grate.
    running rich your plugs will be sooty black. lean would be a whiteish color almost burnt and just right is a dry chocolate brown color. don't worry about the threads just watch the electrode and the porcelain end above it. to do this correctly you have to do a "plug chop" take the ski out on the water and run it wide open. once you reach top RPM, pull the chord and kill it without taking your hand off the throttle. pop the seat and pull the plugs before you restart and see what the color of the plugs are. adjust from there. Yes, the screws are a PIA but that's just the joy of working on these old bitches. it will take a little time to do it right but it will be correct and you wont be "that guy" at the boat ramp with a busted ski holding up the line.
    and its the same thing for the low speed with 1/4 throttle and then pull the key right?
    Is there any other methods worth mentioning or is this the best most accurate method?
    also have you heard anything of the other method I was talking about? While running adjust until you idel reaches peak rpms?
    ive never heard about doing it at 1/4 throttle as you don't really know where that is 100%. you do know where WOT is at though with 100% confidence. as for the idle you do not want to have that thing redlined out of the water. its supposed to be around 3500rpm or just stick it in the water at the ramp and adjust from there till it will run without dying at 1500rpm

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