Arrow kart / Rotax motor, fuel problem:

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  • #42913
    donh
    Participant

    Engine was dying out when running at full throttle on the faster sections of track. Sounds and feels like the engine is running out of fuel. This would result in the engine RPM’s dropping below 5000 before the engine picked back up. Replaced fuel pump, fuel lines, and filter and problem still existed.

    Then discovered that the pick up line inside the fuel tank was cracked which was limiting the amount of fuel being delivered to the pump and carburetor. Replaced the pick up line and all is well.

    Joe thanks for the help troubleshooting this problem.
    😀 😀 😀

    #62351
    Garrick Mitchell
    Participant

    Sounds similar to a problem I had last time out…

    Engine would quit at high RPM or, interestingly, while turning. If I was lucky, could keep the engine running by just barely cracking the throttle open, but too much and it would quit again. Coast to a stop, crank the starter, nothing. [EDIT: Would crank just fine, but not fire at all.] If I sat for a couple of minutes, right about the time the meat wagon got to me, I’d crank it again and it would fire right up.

    The day ended before I could change anything other than the spark plug and battery (no effect), but I suspect I’m having a fuel delivery problem as well. Whether my fuel pump’s pooped or I have a leak in the suction line, it sure seems like the carb bowl is getting depleted enough to cause fuel starvation, whether at maximum demand (high RPM, full throttle) or in a corner (where fuel would slosh away from the main jet in the bowl). Sitting on the side of the track would let fuel siphon into the carb bowl until it filled enough for me to start. I should’ve tried blowing into the vent tube to see if that let me restart sooner.

    #62352
    Rick Schmidt
    Participant

    I would suggest making up a spare system for troubleshooting the fuel supply.

    I made a set up with an extra clunk (the line hanging in the tank) some links of fuel line and a fuel pump. You can attach the pulse line and temporarily wire tie the it on, hook to the carb and tank and go out and try it. If it corrects the problem, start a process of elimination. It is a quick way to trouble shoot what can be an elusive fix.

    Rick

    #62353
    Rick Schmidt
    Participant

    Also Don,

    If you drain the fuel from the tank when the kart is not in use the clunk tubing will last a few seasons. If you leave fuel in the tank, I would replace it every year as it swings back and forth inside the tank and tends to get weak as it hardens from fuel exposure. Use good quality Tygon tubing.

    Rick

    #62350
    donh
    Participant

    Hi Rick,

    Thanks for the feedback it’s greatly appreciated.

    Yes, I used tygon tubing as a replacement. Looked as if the external hose had previously been replaced but the tubing internal to the tank looked to be original.

    I’ve had this problem when running CW at IMI since I purchased the kart last year. I’m glad it’s finally resolved.

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