Kitfox Aircraft Stick and Rudder Stein Air Grove Aircraft TCW Technologies Dynon Avionics AeroLED MGL Avionics Leading Edge Airfoils Desser EarthX Batteries Garmin G3X Touch
Page 1 of 3 123 LastLast
Results 1 to 10 of 27

Thread: Help, I think I soiled my carburetor.

  1. #1
    Senior Member Dorsal's Avatar
    Join Date
    Sep 2008
    Location
    Central, MA
    Posts
    1,511

    Default Help, I think I soiled my carburetor.

    I have run the engine many times (>2 hrs), two weeks ago ran it for the first time off of the wing tanks. Today it will only run with the "choke" on dying instantly if released. My theory is that I did not rinse my tanks well enough or the mo-gass released some spuge that fowled the main carb. I think it runs on the starting carb as this may be a different path for the fuel.
    Any ideas before I disect my carborators? not somthing I am looking forward to given I was hoping for final inspection next week
    Dorsal ~~^~~
    Series 7 - Tri-Gear
    912 ULS Warp Drive

  2. #2
    Senior Member Dorsal's Avatar
    Join Date
    Sep 2008
    Location
    Central, MA
    Posts
    1,511

    Default Re: Help, I think I soiled my carburetor.

    Further inspection and removal of the carbs yields the following unfortunate information. The inside of the carbs and the intake manifold are coated in a brown sticky substance that I believe to be uncured resin from the tanks brought through by the alcohol in the mo-gas. The main and idle jets also appear fowled. The stuff only seems to reveal itself after atomization as the fuel bowl and all preceding elements appear clean. I can clean the carbs, manifold and accessible part of the head, and hope this has not done significant damage to the piston or cylinder walls.
    It's official, today sucks
    Thoughts suggestions or comments?
    Dorsal ~~^~~
    Series 7 - Tri-Gear
    912 ULS Warp Drive

  3. #3
    Administrator DesertFox4's Avatar
    Join Date
    Aug 2008
    Location
    Arizona
    Posts
    3,562

    Default Re: Help, I think I soiled my carburetor.

    Dorsal, this is the very problem I had that keeps me using 100LL religiously. Shortly after phase one, I was going to "self fuel" with auto fuel to keep my operating costs lower. I went through one fill of auto fuel (with alcohol) OK. Then topped off and did not fly for a couple days (maybe 3 or 4). Started the Kitfox in front of the hangar and shortly it was running rough and getting worse. It finally killed completely.
    Removed pilot's side air cleaner and stuck my finger inside the carb to check the slide and my finger stuck to the side of the carb. Not a good sign. Took off the bowls and found brown milky looking fuel in both. Definitely dissolved resign.
    Took both carbs off and removed every part from them. Everything was coated. Carb cleaner barely made a dent in the goo. Took about 3 cans per carb and lots of tender cleaning with brass brushes so as not to scratch the carbs and parts. Magnifying glass to inspect all the little nooks and crannies. I also ordered two Bing carb rebuild kits from Phil Lockwood for reassemble. I think the diaphragms were ok and did not need replacing. After cleaning, rebuild and assembly it ran great again.
    Dorsal , after removing the carbs from the manifolds I found no contamination inside the manifolds. Didn't seem to affect the engine at all. I checked the plugs of course and found no contamination there either. Fuel pump seemed unaffected as it ran great after start up again. Also my fuel flow sensor worked as new so I was lucky there too. I was down about a week. My tanks do not play well with alcohol laced fuel. I've run 100 LL Av-gas completely since the two tanks of car gas and have had zero problems. I use Decalin as directed and change oil/filter every 25-30 hours. No plug fowling ever. They come out the perfect color after 100 to 150 hours in service.
    Good luck. You've got a little tinkering to do but hopefully the engine should be ok.

    Obviously you should drain all the contaminated fuel out of the aircraft and take a look inside the tanks. Mine seemed fine after rinsing with a little av-gas to flush them out. They are not soft to the touch and seemed to recover completely with no leaks. Replace your fuel filters also.
    Dorsal as a P.S. do you know how old your tanks are?


    DesertFox4
    Admin.
    7 Super Sport
    912 ULS Tri-gear


  4. #4

    Default Re: Help, I think I soiled my carburetor.

    huge bummer as I know you were ready to cross the finish line... but, obviously, it could have been worse... better to identify the problem during testing...

    I was involved in the "plastic" gas tank industry a few years ago and learned a great deal about gas tanks and the lines that serve them. I was astonished to learn how much damage ethanol does to fuel systems. The Marine industry is suffering greatly. cross-linked poly eth. roto-molded tanks and non-coated aluminum tanks (ethanol does a number on the coatings within certain aluminum tanks) are the way to go now...

    What type of tank did you use?

    If the tank is ok... did you use a sealant in the fuel lines that perhaps migrated from the outside to the inside of the fuel line?

    Hang in there... everyone's still healthy ; )

  5. #5
    Senior Member Dorsal's Avatar
    Join Date
    Sep 2008
    Location
    Central, MA
    Posts
    1,511

    Default Re: Help, I think I soiled my carburetor.

    Sooooo, being the type to turn into the storm and remembering the post from DF4, I bought some carb cleaner and spent the day disassembling, cleaning and reassembling the carbs. I also cleaned out the intake manifolds which where quite sticky inside. I think I caught it early enough as it only took me one large can of cleaner and about 6 hours. My objective at 9:00 this morning was to test full power to confirm my prop pitch and balance the carbs with my CarbMate. Just came in from running the engine (clean fuel in the header tank), smooth and solid, achieved 5250 WOT (target > 5200). Did not get a chance to use the CarbMate but all in all a long day that no longer completely sucks.
    (will be running 100LL as soon as I get to the airport)
    Thanks DF4 and Andrew for the support
    Last edited by Dorsal; 06-13-2010 at 04:16 PM.
    Dorsal ~~^~~
    Series 7 - Tri-Gear
    912 ULS Warp Drive

  6. #6
    Administrator DesertFox4's Avatar
    Join Date
    Aug 2008
    Location
    Arizona
    Posts
    3,562

    Default Re: Help, I think I soiled my carburetor.

    Glad you made quick progress Dorsal. Sounds like your engine is fine and making full power again. D@%#ed alcohol. Love it in my martini's, not in my fuel. The CarbMate will get it running like a fine Austrian watch.
    Wondering what that "sludge" would have done to a fuel injection system.


    DesertFox4
    Admin.
    7 Super Sport
    912 ULS Tri-gear


  7. #7
    Senior Member cap01's Avatar
    Join Date
    Apr 2009
    Location
    yelm, wa
    Posts
    694

    Default Re: Help, I think I soiled my carburetor.

    kind of wondering why filters dont catch this crap before it get to the carbs ?
    chuck
    kitfox IV 1050
    912ul warpdrive
    flying B , yelm, wa

  8. #8
    Senior Member Dorsal's Avatar
    Join Date
    Sep 2008
    Location
    Central, MA
    Posts
    1,511

    Default Re: Help, I think I soiled my carburetor.

    I believe it is because it is in solution, when the atomized fuel coats the walls of the carb and intake manifold the fuel will vaporize depositing this stuff. I expect that the filter is clean (will replace anyway).
    Thats my theory.
    Dorsal ~~^~~
    Series 7 - Tri-Gear
    912 ULS Warp Drive

  9. #9
    Senior Member cap01's Avatar
    Join Date
    Apr 2009
    Location
    yelm, wa
    Posts
    694

    Default Re: Help, I think I soiled my carburetor.

    thats a reasonable explanation but since your building a model 7 , a person would think that youd have the latest tanks . so far weve been lucky , another kitfox and mine , and been able to get gas without alcohol . im sure a day will come when its not available . there is no common sense on the left coast
    chuck
    kitfox IV 1050
    912ul warpdrive
    flying B , yelm, wa

  10. #10
    Senior Member Dorsal's Avatar
    Join Date
    Sep 2008
    Location
    Central, MA
    Posts
    1,511

    Default Re: Help, I think I soiled my carburetor.

    The tanks for my seven where probably built in 01-02 time frame, might have to swap them out someday but for now its 100LL and Decalin for me.
    Dorsal ~~^~~
    Series 7 - Tri-Gear
    912 ULS Warp Drive

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •