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Has anyone experienced problems with the new type of rubber gaskets p / n 830721, for the caburetors on Rotax 912 & 914, when the engines are running on E10 fuel?
We have experienced several times that the rubber swells up and the swimmer's body leaks.


Let me hear some comments !

FinnS

  • Re: Rubber gasket Carb. housing

    by » 6 weeks ago


    @Finn:  Please fill out a CSIR report on this issue.

     

    See this link for instructions https://www.rotax-owner.com/en/support-topmenu/csir-service-information-report

     


  • Re: Rubber gasket Carb. housing

    by » 6 weeks ago


    We run mostly all 91 oct. with ethanol here in Arizona and to my knowledge haven't heard or seen this. When I do annuals I always pull bowls off and haven't seen this. It would be interesting to see this out. You could drop a gasket into a jar of 91 oct. with ethanol.  I have to go to the field in the morning. maybe if I can remember I'll do that.


    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-574-1080 Home (TRY HOME FIRST)
    520-349-7056 Cell

    Thank you said by: RotaxOwner Admin

  • Re: Rubber gasket Carb. housing

    by » 5 weeks ago


    Finn.

    I had a similar issue with swollen rubber a few months back. It might be also worth checking your diaphragms.

    I was using cork gaskets so did not show there. 

    It was ethanol free fuel.

    Here in New Zealand a fuel company started selling 100 octane mogas. It looked like it was going to be a fuel from heaven for Rotaxes, No lead issues &  would keep its octane level for 6 & maybe out to 12 months.

    Before using it I contacted them to see if any issues with rubber components (I operate over very hostile terrain.)

    I was told they had not seen any. It could however discolour certain plastics if they were then exposed to UV. That did not really concern me as my tank fibreglass.

    After 40 hrs of running on  it the engine seemed to be performing as before however when removing the diaphragm caps to replace the carb needle circlips they jumped out like a Jack in the box. Very swollen. (See pics) It was 36 hrs since last flown.

    After sitting on the bench for 12 hrs they returned to normal size. 

    I contacted them again and their thoughts were it was not the fuel causing it. I then did an immersion test asRoger mentions above. Yes it was the fuel. Probably some stabilisers they had added.

    After new diaphragms & O rings now flown 200 hrs and all good.

    Wrote an article in our aviation mag warning others.

    Pete Avery

    26577_2_8CD72FB4-D1A2-4E27-8FC5-20253CD6840E.png (You do not have access to download this file.)
    26577_2_5E71080A-4F7A-4479-AFD8-9C4FAA4D3177.png (You do not have access to download this file.)

  • Re: Rubber gasket Carb. housing

    by » 5 weeks ago


    I over cropped the pic above.

    here again.

    26578_2_FE1D25A2-CAE9-4D08-BE65-EB2CC29E1620.png (You do not have access to download this file.)

  • Re: Rubber gasket Carb. housing

    by » 5 weeks ago


    Also forgot to mention changed diaphragms, O rings and went back to running on 95.


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