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Motor will start but won't stay running

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  • Motor will start but won't stay running

    Hello all, I'm a newbie to this and looking for help. I have a 1985 Yamaha 90etlk 2 stroke it will start and run at WOT but die seconds after putting it to idle. I have cleaned the carbs checked if I'm getting gas to the bowls and checked the sparks and everythink seems to be good ( spark plugs are sparking and removing drain plug from carb and gas is coming out) I'm at a loss here and need some insight as now I don't know where to begin thanks in advance!

  • #2
    did you follow the link and sync procedure after installing the cleaned carbs?
    did you check timing with a timing light to make sure it is in spec and advancing and retarding as it should?
    did you clean out the lines and pump before installing the cleaned carbs?


    • #3
      Originally posted by TownsendsFJR1300
      Is the engine new to you?

      I gather you've heard it run correctly previously. (Yea, nay?)

      Has it sat for awhile with old, untreated fuel in the engine?

      **When you cleaned the carbs, did you remove the main and idle jets(and look thru them)? Or just spray the outsides? (be honest please)...
      Yes it ran previously, it did sit for a little while in garage and I took out main jet and cleaned them in all 3 but not the idle jet (which now that I think of that it is probably a good idea to get to those and clean them)


      • #4
        Originally posted by TownsendsFJR1300
        Yep, the high speed jet gets the high RPM's, the low speed jets, low speeds..
        Make sure ALL the openings are clear(you can see thru them.

        If the fuel is older than a month and un-stabilized, it's likely bad. Dump it and get fresh fuel B4 trying to crank it up again. Un-less you enjoy "do-overs"

        Those idle jets are pretty darn small and easy to clog...

        If there's air screw adjusters on the side of the carbs, gently turn them in and RECORD the settings. Remove for cleaning, then re-install when all done..

        Plz post back how it goes...
        Just got the motor back together and what do you know it idle like a CHAMP! Thank you so much it was an over sight on my part the idle jet was covered by a rubber plug and I took it off and the jet was covered in gunk. Thanks for all your help!