Is Fuel Starved Motor Revving Normal

Discussion in '2-Stroke Engines' started by Jason74, Jul 10, 2009.

  1. Jason74

    Jason74 New Member

    When I forget to open my petcock or run out of fuel, the motor revs like crazy on the last bit of fuel (whether I am giving it throttle or not).

    Now, I know that I have read that this happens to others; however, what I can't remember is whether or not it is normal or if it is a sign that the engine in running too lean or rich. I have tried to search for the original post that I have read, but I have had not luck. So can someone tell me whether it is normal or whether it means that something is out of whack?


  2. ratty

    ratty New Member

    That is a normal. It indicates a lean condition. Try not to let that happen as is could cause engine damage. Not likely, but possible.
  3. Skyliner70cc

    Skyliner70cc Active Member

    Its normal as your engine leans out. This should not cause engine damage since the lean run doesn't last long enough to cause any significant heat buildup and residual oil in the crankcase bottom is still splash lubing things.
  4. when mine ran out of gas, the engine just stopped.
  5. Skyliner70cc

    Skyliner70cc Active Member

    If you were at idle and it ran out of gas without increasing in speed just before dying, it means your low end mixture setting is lean.

    Many in the RC hobby use the pinch test (starving engine of fuel momentarily) on fuel lines to determine if their carb mixtures are set correctly. not practical on our engines but follows same principle.
    Last edited: Jul 10, 2009