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This topic contains 6 replies, has 4 voices, and was last updated by  Mark Traylor 1 year, 3 months ago.

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  • #78041

    Daniel Gauci

    I’m about to purchase a used Rotax Max kart as my first kart and I went to test it. I thought the engine drove well other than some bogging down during corners (I assumed that this was because I was driving at a very low RPM). However the engine stopped running at some point. However the owner told me that there was some air trapped in the fuel lines and the fuel was not reaching the engine. After blowing into the fuel tank and spraying some brake cleaner, the engine started again.

    I’m guessing that things like this do happen (especially when considering that the kart was just filled with fuel after being empty for a while), and it’s nothing to be worried about right? Any opinions would be appreciated.

  • #78043

    Tim Landon

    If the seller knew what he was doing.  That should not have happened.  IMO.

  • #78044

    tony zambos

    I would be hesitant to buy any 2-cycle engine that may have been sprayed internal with brake cleaner. Bogging did occur with older motors if throttle was applied too quickly.
    Guessing that it stopped either do to a weak battery or the fuel pump needs rebuilding. The rebuild kit is cheap.

    If everyone near you are racing motors that have been upgraded to an EVO, you will be at a disadvantage. Check first. Also find out how long ago the motor has been serviced.

  • #78084

    Daniel Gauci

    Thanks for all the replies. Locally most karts do not have the EVO engine so that shouldn’t be that much of a problem, especially considering that this will be my first kart.

    Here are some videos showing the kart running well, bogging down in corners and shutting down. Not sure if they can be of any help in indicating the condition of the engine. As you can see, I’m driving the kart extremely slow, which I thought could be a contributing factor (tires were really bad and it was my first time driving a non rental kart).

    Driving well: https://www.youtube.com/watch?v=m0U7Co_f9Oc

    Bogging down: https://www.youtube.com/watch?v=jo0i8BHa0SU

    Shutting down: https://www.youtube.com/watch?v=anG-q3r6Bi4

  • #78089

    tony zambos

    Ask the seller to drive the kart with your go-pro to see if the issues were you or the kart.
    Yes, you driving at partial throttle could be the cause. A list of possible causes would be: fuel pump, external fuel filter, fuel filter in the carb, carb floats, carb jetting, RAVE valve stuck open, low fuel level, poor fuel pick up, exhaust packing clogged, weak battery, fouled spark plug. That list is in no particular order of importance or likelihood.
    There used to be a good bit of literature on the web on Rotax FR125 engines. Read as much as you can.

  • #78090

    Mark Traylor

    You may have fouled the plug driving off the throttle so much. They are sensitive to throttle application. I will warn you about buying a used kart especially a used rotax. Depending on its age and state of upgrade you could need more money in upgrades than another updated engine will cost. Buying the “cheap” out of date kart will typically cost you more in the end than buying something newer and updated from the start.

  • #78091

    Mark Traylor

    pictures of the engine would be of help in identifying what may need to be done

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