912 IS engine starts astero and vibrates a lot, then it works perfect

Can you please clarify your “throttle set to 70%” comment vs. the 50% setting indicated on page 3-9?  I’ve been following the 50% direction.  Is 70% better to use?

If you are having issues with vibration at 50% throttle position, try with the throttle at 70% and then throttle the lever back to the idle (roughly 2000 RPM) after the engine starts. 

70% throttle position is the "sweet spot" for most of the 912iS engines at startup.

I agree with Rotax and start all my engines with the throttle cracked which usually results in about 2K - 2300 rpm on start vs a way too low start rpm that beats things up. This way your engine like others should have a smoother start.

Give it a try and let us know.

50% throttle setting on mine results in around 2800 rpm on starting.  I then have to lower it to get down to 2000.  So, should I stick with my 50% setting on start, or increase to 70%?

Bob

Are you having issues with starting and vibration at the 50% throttle position?

If the answer is NO then stay at the 50% throttle postion.

If the answer is YES, then try starting at the 70% throttle position.