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Why YOU should Check the Idle on a Rotax 912 before each flight

Posted by Brendan OMara

We think there’s still a lack of knowledge on how the carb works and engine mechanics in general in the private pilot community.  Even a rudimentary knowledge of plugs, mags, solenoids, pistons, and exhaust can help a lot in the event of an emergency.

To answer the question – we’re not Continential or Lycoming experts, but we know some things about experimentals and the Rotax world.  Those dual carb Rotax 912′s use push pull levers to control the throttle.  In certain aircraft you can pull hard enough on the throttle to close the intake completely, killing the engine.  The problem with Rotax gear driven motors is how fast they stop; they don’t windmill as well as a direct drive motor, so getting that restarted will require MORE steps than simply advancing the throttle again.  No one should create their own in-flight emergency, so verifying the throttle stops are set to prevent killing a Rotax at idle is quite important. 

In addition, dual carb systems can be quite out of sync its important to test the whole range of power settings to verify it’s at least ‘semi-smooth’ across the board.  With more and more Rotax powered LSA’s worldwide, this is an important pre-flight step in our opinion.

Next time you fly, please check your idle setting, and pull back pretty firm (not enough to break anything, but make sure you are to the stops).  If you’re in an emergency state or under stress, you’d be amazed how you might just pull that throttle a little harder to idle that you intended – make CERTAIN such an event never stops your motor, or things could get worse in a hurry for you.