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  1. #1

    Join Date
    Apr 2019
    Posts
    2
    Location
    Ohio
    Mower
    John Deere

    JX75 Surging at Idle- Normal?

    I bought a used JX75 last year that surges at idle but runs fine at full load. I used it a few times last year without problems and now have the time to remove and thoroughly clean the carb. However, I stumbled across this YouTube video where the gentleman claims this is quite normal due to the blade brake clutch system. I'm skeptical but don't want to fix something if it isn't broken.

    Refer to video at the 30:00 minute mark.... Your thoughts?

    https://www.youtube.com/watch?time_c...&v=CeHD75tQKdg

  2. #2
    Oliver Douglas's Avatar
    Join Date
    Apr 2019
    Posts
    16
    Location
    Pacific North Wet
    Mower
    14SBC STX38

    Re: JX75 Surging at Idle- Normal?

    Sounds like a restriction in the air circuit.
    About the only thing you can do is sonic clean it and hope the blockage leaves, bore our the main jet to enrich the mixture, risky business for sure.
    Or change out the carb, but it will only happen again if any debris falls into the tank. I put a 100 micron filter on mine a few years ago. Does not seem to make any difference, so what we are dealing with in stuff right from the pump. In the old days we used to use paper coffee filters to pre-strain the fuel at the pump.

  3. #3

    Join Date
    Apr 2019
    Posts
    2
    Location
    Ohio
    Mower
    John Deere

    Re: JX75 Surging at Idle- Normal?

    Quote Originally Posted by Oliver Douglas View Post
    Sounds like a restriction in the air circuit.
    I agree and I'm willing to fully disassemble the carb, clean out the orifices, spray with carb cleaner and cook in my ultrasonic cleaner. It certainly won't hurt but I didn't want to waste the time if the surging is truly caused by the blade brake clutch.

  4. #4
    tom3's Avatar
    Join Date
    Apr 2018
    Posts
    349
    Location
    Ohio
    Mower
    John Deere

    Re: JX75 Surging at Idle- Normal?

    I've had a couple engines that "hunt" when under no load, adjust the carb (lean it out some) to smooth it out and then it stumbles when the load hits. If not excessive I'd probably live with it.

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