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Two questions Overheat on climbout-#1 plug carbon

in 912 / 914 Technical Questions 10 years ago
Hi All,

First post. I have a 2008 sportcruiser and am based in SC. On warm summer days my oil temp goes into the yellow (221-226 degrees) during normal climbout. Engine RPM is 4600-4700. Is this normal? Also #1 cylinder plug always appears to have dry carbon on plug. The other three plugs appear to be normal and have the slight burnt orange color. Is this okay?

Maneuvering speed of the sportcruiser is 80 knts. My rpm is then only about 4600. Since summer months in SC are hot causing a lot of thermals and cruising at 100-115 knts (5000-5300 rpm) bounces you all over the sky what is the alternative except repitching the prop? I swing the Sensenich three blace prop pitched at the #4 position.

  • Re: Two questions Overheat on climbout-#1 plug carbon

    by » 10 years ago

    Hi John,

    First 221-226F is what I would consider very normal on climb during warm months and even higher for some folks. If you are checking plugs after idle long you will probably find some with a little dry black soot. You should really be cruising over 5000 rpm and not down in the low to mid 4k range. For a reasonably balanced rpm with that prop which I also have, around 5600-5700 rpm at WOT at your average cruise altitude is a reasonable place to be. You need to run it WOT and check the max rpm. Run the engine at 4k for a few minutes and then shut down and check the plugs without any extended idle time.

    p.s.
    You can set that prop by hand far better than you can with those pins.

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

      
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  • Re: Two questions Overheat on climbout-#1 plug carbon

    by » 10 years ago

    Thanks for the repy!

    Normally when the oil temp goes into the yellow (221 degrees) I back off on the throttle and reduce my rate of climb. Have never tried to push it and see where it does ultimately go.

    I only get a little soot on cylinder # 1. The other three are always okay. Will try your suggestion and run at about 4000 rpm for five minutes on ground. Usually I check plugs after a flight and maybe a two or three minute taxi to the hanger.

    My service and maintenance manual says I should use pin # 4 with the Sensenich three blade prop. At this setting my climbout rpm is 4600-4700 rpm at 60 knts. In smooth calm air WOT I am getting the 5600+ rpm and pushing 120 knts.I normally cruise at about 5000-5200 rpm with indicated airspeed 105-115 knts. unless there are a lot of thermals. I then usually slow down to 80-90 knts. but then my rpm is down 4600-4700.

    I didn't have any problem setting the pitch with the pins. I just left the pin in and tightened down the bolts per blade. I then left the two outer bolts tight and loosened the two inner ones and moved on to the next blade and repeated the process.

    I also am a LSRM. However, I only work on my plane which is a SLSA. The cost of the school really paid off when I had to do my five year rotax rubber replacement.
      
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  • Re: Two questions Overheat on climbout-#1 plug carbon

    by » 10 years ago

    Hi John,

    The WOT rpm sounds pretty good. The yellow oil temp range should start around 230-231F. If you only see 240F max on a hard climb out it I wouldn't sweat it because it should come right back down to some where around 200-220F which of course is affected by OAT's and engine air flow and radiator exposure.

    I did a research project about 2 years ago using Sensenich and 4 other prop MFG's and got to fly 4 identical planes with different props side by side. Using the pins on all those props was a pain and it left blades not in equal pitch with the others. I hand set all of them. When I talked to the engieer's at Sensenich they said the same thing. The pins look great on paper, but you can do a better job by hand. I also had a hard time pulling the pins out after I had the blade secured.

    You may want to put a level either digital or bubble and or a prop protractor on your prop to make sure they are all equal.

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

    Thank you said by: YEN NIEN YU
      
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