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Running Carbs Dry?

in General Tech Discussion 11 years ago
Is there anything good or bad about turning OFF my Master Fuel Valve and letting my 912ULS (in RV-12) just die from fuel exhaustion as I taxi up to my hangar at the end of a flight? Of course, I keep my engine RPMs low (@1,650 rpms) just before the engine dies. Is there any benefit or problem to shutting OFF the fuel like this? Thanks!

  • Re: Running Carbs Dry?

    by » 11 years ago

    Hi David,

    Why do you want to drain the bowls?

    If you are going to fly again in a week or so there is no real need to drain the carbs. I would only do that for long term storage or a long down time. That would also mean that pump is sucking hard against a dead end. That fuel in the bowls will be okay for a few weeks without any issues. I also wouldn't let my 912ULS 10.8:1 (or 11:1 if you like) compression ratio engine idle down at 1650 and beat on the gearbox or cause enough vibration to wear on components like mounts and the like. If you are just going to set on the ground and let fuel drain with rpm then idle at or above 1800. When you go to shut down then pull back to the slower rpm for a moment and turn the engine off.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell

      
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  • Re: Running Carbs Dry?

    by » 11 years ago

    Thanks Roger for your learned input. I was figuring that by running the bowls dry, there would be no residual fuel to breakdown over time. I worry too much I guess! ;<) I'll stay with the recommended shut-down procedure since I've been flying my RV-12 at least once a week. Thanks again.
      
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