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Getting a new 912ULS installed in my sport cruiser and was wondering just how to approach the new engine as far as cruise rpm, use of fuel additive and any other advice I can get? including Sensenich prop pitch setting. I am in Texas so its hot in summer and I need climb power. In the winter I would like to go to more of a cruise pitch. I THINK. I haven't changed it yet and only watched it done once. But I think its something I should see for myself. How and where I fly. 

  • Re: Breaking in new engine. run ?

    by » 7 months ago


    No additives. Make sure you do a good oil purge before running it. There is a video here on the website and it's in the manuals. Once you start it up and it's all warmed up then do a mechanical and pneumatic sync on the carbs. Do the sync again at 25 hours because things like the throttle cables will settle in and stretch here and there.

    As for the prop pitch try setting a static for around 4700 rpm. Then go fly. Go up to your average altitude like on a normal flight. If you normally cruise at 6K feet then go there and then apply full throttle.The "best balanced rpm) and sweet spot rpm for climb, cruise, engine temps and fuel economy rpm is 5600 - 5650 for a ground adjustable prop. Anything under 5500 is over pitched and you start losing everything plus you stress the engine. The more under 5500 rpm WOT the worse everything gets. If you have a special need for a better climb prop over a well balanced climb / cruise prop then 5800 WOT is better, but you'll lose a tad of cruise at that setting.


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


    Thank you said by: Carlos Quijano

  • Re: Breaking in new engine. run ?

    by » 7 months ago


    Hi Charles,

    Roger L knows that I have a slightly different opinion on fixed/ground adjust pitch setting for static rpm.

    Rotax recommend 5200 rpm Static - in most applications this will give you excellent TO/Climb performance, with minimal stress on the engine. Sure you won't get the very best Cruise speed however fuel consumption per hour will likely be lower, as will temperatures (than for a courser pitch). This setting will also be less impacted by Density Altitude issues, terrain clearance and aircraft load. 

    Very slippy airframes, are likely to derive more benefit from Rogers advice, than draggy ones - eg Sonex might do very well (140 knots?) Zenith STOL likely struggle to get 105 knots, no matter what you do. 


    Thank you said by: Carlos Quijano

  • Re: Breaking in new engine. run ?

    by » 7 months ago


    Thank you. I have been watching your reply and want to thank you for the help you give us. 

    I will try this next flight.


  • Re: Breaking in new engine. run ?

    by » 7 months ago


    Thank you. Sounds like good advise. I'll check that out. i got some researching to do for sure.


  • Re: Breaking in new engine. run ?

    by » 7 months ago


    Hi Sean, there is some rotax document that recomends the 5.2k static? Do you mind to share that? I like to read. That is why I’m asking… Thx.


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