fbpx

 

912 ULS  2-01, SN 9571011, Hobbs: 3 hrs, Purchased 16/05/2019 (no longer under warranty)

Background: 

Fitted to a home built Sonex (A) - as happens all to often, this brand new engine purchased way too far in advance of use - warranty lapsed.

This engine has only recently been started for the first time. Full oil purge, as per Rotax instructions. After first start, carburettors balanced. Undergoing static (non flying) testing to fine tune cooling. On its half dozen or so starts it "caught" very fast, every time, including last start.

Today:

After some cowling modifications (surgery), I started the engine this afternoon - no problem. Cooling improved but still getting too high. Stopped engine and removed cowling, for further surgery. After about 1 hrs shut down, replaced cowling and tried to restart  - CLICK!.

Investigation has found:

Battery in top condition delivering expected power to starter solenoid/relay.

Starter motor tested  "open circuit"/no continuity - suspect damaged brushes.

Starter motor is HD varient.

Have checked out Heavy Maintenance, Section  80-00-00, Electric Starter and Illustrated Parts Catalog, Electric Starter, Section 80-10-00, 

I welcome all your analysis/diagnosis/remedial suggestions. 

  • Re: 912 ULS - No Crank

    by » 6 weeks ago


    Two supplementary questions:

    Who makes the Rotax HD starter motor?

    Is there a reputable "after market" supplier of suitable parts for Rotax starter motors OR whole motors?

     


  • Re: 912 ULS - No Crank

    by » 6 weeks ago


    I would work out why the starter is measuring open circuit. Does it continue to measure open circuit if you connect a resistance meter between the +ve terminal and the casing whilst rotating the shaft by hand. If it is only open circuit in one position then it is likely that a single winding is open circuit. If it is measuring open all the time then I would suspect the brushes or their connections.

    It should be straightforward to open it up and take a look inside and using a resistance meter work out what has gone wrong.

    Let us know what your find.


  • Re: 912 ULS - No Crank

    by » 6 weeks ago


    Update;

    Removed & opened starter motor - what a mess! Part  of windings melted. Presumed seized, causing wire from positive terminal, to brushes, to melt. Will contact Rotax agent seeking warranty - definite manufacturing fault.


  • Re: 912 ULS - No Crank

    by » 6 weeks ago


    If your (or clients) very low time Rotax starter motor has died - please let me know.


  • Re: 912 ULS - No Crank

    by » 5 weeks ago


    Sean Griffin wrote:

    If your (or clients) very low time Rotax starter motor has died - please let me know.

    So the answer is - no one has had a low hour starter motor failure ???????


You do not have permissions to reply to this topic.