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Hard starting 912

in General Tech Discussion 7 years ago
I am having a hot starting problem with my 912 A , when hot but only when using 100LL and hot weather. The engine will not fire while cranking at any throttle setting. The odd thing is I can change as little as one plug and it starts normally. This will occur even with plugs that are new and only have one flight on them. The engine has 500 hours and has been ran on 91 octane pure gas. If the engine cools down overnight it will usually start normal most of the time. Plug DCPR7E gapped to .028.

  • Re: Hard starting 912

    by » 7 years ago

    Reduce the gap to .025 and try again. .028 may be causing part of the problem, it's too wide.

    Choke or primer system? When was the last carb sync and were they synced at idle?
    Are you using full choke on the first cold start? Do you have carb drip trays installed? You may be boiling the carb bowl fuel. You could also try wrapping the exhaust.

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

      
    Report

  • Re: Hard starting 912

    by » 7 years ago

    Hey Roger thanks I will try .025 gap. I use a primer and I do have carb trays installed. The carbs were synced about a month ago. The only time this happens is when I am traveling and use 100LL, happened last year on a trip also and didn't happen all year until I stared traveling again.
      
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  • Re: Hard starting 912

    by » 7 years ago

    Hi Paul,

    I know the problem and you won't like it.
    Dump the primer setup. They are terrible. The regular enricher (choke) circuit works ten times better. It's cheap and easy to put in. Just buy a pull cable, drill a hole in the dash, run the cable ends to the carb chokes through the fire wall. It's easy and it will make those hard starts go away. I have done many and they all worked well and the customers were happy.

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

      
    Report

  • Re: Hard starting 912

    by » 7 years ago

    Ok thanks I will give it a try l do use the starting carb on my Jabiru and felt that the primer system worked better. It will be easy to try but I don't understand why the problem only appears when I use 100LL and why changing a plug allows it to start. Anyway if it works with the starting carbs I will be happy but still puzzled
    Thanks Roger it will be a few days before I get to try it out but I will let you know.
      
    Report

  • Re: Hard starting 912

    by » 7 years ago

    You really will like the normal choke setup a lot more than a primer system.

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

    Thank you said by: Paul Spackman
      
    Report
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