HI guys I'm all new to the aviation world, and I've found an aircraft that I am thinking of buying, and after reading online about the 912uls it seems like it is a solid engine.

But I have heard that some earlier ones had a few weaknesses and I am trying to find out wether the engine the is on the aircraft I want to buy are one of them. how do I go about that? or does anyone know?

The serial no on the engine is 5651174

Thanks! /Oskar

  • Re: 912uls known weaknesses?

    by » 5 months ago

    • Serial Number: 5651174
    • Engine Model: ROTAX 912 ULS
    • Manufacturing Date: 18.04.2008
    • Time Between Overhaul (TBO): 1500 hours

    Although the engine originally came with a 1500-hour TBO, it can be extended to a 2000-hour TBO due to the presence of the "heavy case," which mitigates case fretting. This fretting issue was prominent in 912 ULS engines manufactured before 2007.

    If you are considering purchasing a Rotax-powered aircraft, please view this video that covers the pre-buy inspection of a Kitfox aircraft powered by a 912 ULS engine. The video offers valuable insights into what to look for and what steps to take if you are interested in acquiring a Rotax-powered aircraft:

    Pre-Buy Inspection Video

    You can also find information on any Rotax-released Airworthiness Directives (ADs) or Service Bulletins (SBs) related to your engine by clicking on this link:


    Additionally, check the engine logbook to ensure compliance with these directives.

    It is highly recommended that you undergo a Rotax service course for a better understanding of your Rotax engine and how to properly maintain and operate it. This course is strongly advised:

    Rotax iRMT Training

    Thank you said by: Oskar Öhrström

  • Re: 912uls known weaknesses?

    by » 5 months ago

    Hi all

    The actual change on the case was in 2006.  Mid 2006 they changed the way they did the crankcas serial number.  All the old formula serials were consecutive, that is one number per case.  An example would be 20123, then 20124, followed by 20125 and so on.  Mid 2006 they went to a year serial format.  The first serial for the new crancase design was 10.0010.  the first 2 are the year of producetion, 2010 is 10.  The balence is the serial within that year.  So for example today 23.1234 would be production year 2023 and the 1234 th case of that produiction year.  

    Check your crankcases just between the mid point of the block between the push rod tubes from the side.  The case serial is located there. 


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