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912 ULS Weak Cyinder

in 912 / 914 Technical Questions 9 years ago

  • Re: 912 ULS Weak Cyinder

    by » 9 years ago

    Man I hope you're right. I guess my surprise was that it has always looked much better, even as I approached 50 hours. The only difference with this run is that I did use 100LL on one leg of our cross country. I immediately noticed the black oil on my next preflight. Maybe I am just paranoid. As soon as my oil analysis kit gets here, I will do a warm up, run the compression test, and take my sample during an oil change. That, and cutting open the filter may offer a bit more info........tom
      
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  • Re: 912 ULS Weak Cyinder

    by » 9 years ago

    Hi Tom,

    I doubt you will see anything in the filter that is noteworthy if the oil magnetic plug is clean which should be checked each oil change. I like to do oil analysis too at the annuals, but usually don't bother for the first 200 hrs. I use AvLabs. They have a huge data base on Rotax engines and compare your oil sample against others within that approximate hour time frame. They test each sample 3 times and will call you if anything is flagged as a red alert. Cost is about $20 and you can get results and compare old samples right online. You may see samples through the years with a little high level of this or that, but usually change on the next sample. When you drain the oil make sure you catch a sample at about 1/2 tank of oil drain. Right at the beginning of the drain or towards the end of the drain will skew your results. Some contaminants sink and some float.

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

      
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  • Re: 912 ULS Weak Cyinder

    by » 9 years ago

    Roger, any ideas on why he would have a low compression cylinder on such a new engine?
      
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  • Re: 912 ULS Weak Cyinder

    by » 9 years ago

    Hi Garrett,

    Many think they have a low cylinder, but the only way to know for sure is a compression test. So we'll have to wait for his results. I kind of doubt he has a low compression with that new an engine.

    Two things I ALWAYS remember,
    Never put the cart before the horse and always do a diagnostic starting at "A" then b,c,d,e, ect... Fail to plan and mess up either one of these and you may spend money and chase your tail for weeks.

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

      
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  • Re: 912 ULS Weak Cyinder

    by » 9 years ago

    Well, I'll sleep better tonight!! My oil analysis kits came in yesterday, and I went to work this morning. First, the engine has been sitting for the past 3 months while we were wintering in Florida. After a 10 minute warm up to get the oil up to temp before draining, I found during the post run gurgle step that all of the cylinders felt pretty good. I drained the oil, took my sample, changed the filter and filled with fresh oil. I gave the old oil the finger rub test, and it felt pretty good. Also, the oil was pretty black, but it didn't really show any signs of contamination. When I did the compression leak test, I found 1 cylinder with a 2 pound loss, and the other 3 were closer to a 4 pound differential from the input air pressure. I was quite pleased to see that. From the results of todays actions, I feel confident that Roger was correct from the start, and that I had nothing to worry about. I will post the lab results on the oil, but I really don't expect to hear anything bad. Thanks to all who took an interest in my perceived problem. It's terrific to have such a fantastic support group....Tom
      
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