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:(

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 :mad:
Thoughts suggestions or comments?

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?

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 ; )

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

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.

kind of wondering why filters dont catch this crap before it get to the carbs ?

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.

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

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 . i think my tanks were circa 1991 - 1992 . i replaced one last winter and ill do the other next winter . besides the alcohol issue i needed larger tanks , i originally had two 6 gal tanks . just not enough gas to go anywhere and get back without refueling .
have you scheduled your inspection yet . must be getting close .

Very similar to the vintage of my series 7 tanks, which were made just 6 months before the switchover to the different resin. Oh well, someday in the future we all will have a tank replacement party... or they will finally give us some alcohol free unleaded at the airport!

andy , we were getting alcohol free gas right by the auburn airport at the station that sold the trick gas , untill a few months ago . sadly they dont handle it anymore . another holdout gave in .

Fuel Filters. I would suggest that anyone using mogas to not use paper fuel filters. They will clog with this residue. I've been flying my Trike for 10 years now on mogas. I have a poly tank and see through blue fuel lines that I change every year. Haven't had any problems with this set up. The Fox now, well, it has fiberglass tanks and I will either run 100ll or fine a gas station that carries non-ethanol when the time come to fire it up. There are a few stations in Pa. that offer non-ethanol gasoline.
One of the guys in our EAA chapter works in the petroleum industry. He says you can order a tank load of non-ethanol right from the refinery. Only problem is that you will have to find a place for 3k gallons of the stuff. The gasoline suppliers get a tax break if they put the ethanol in at the time of delivery so expect to pay more for non-ethanol fuel. Other than that, it is a useless venture all around.

Next Chapter, clean carbs now what.
Turns out the brown sticky stuff coated the inside surface of both wing tanks, both tanks had been rinsed before installation but that had little effect on this stuff. Very fortunately for me Andrew G wanted to come up and see my plane offering to help with what ever was the task of the day. With his help we took a wing off and sloshed the tank with 1/2 gallon of acetone. Draining this into a white bucket revealed a mixture with the color of "slightly" weak coffee. Doing this twice more resulted in weak tea, then basically clear, we then sloshed with a gallon of clean fuel just for good measure. Did the second wing (about two hours per wing, THANK YOU Andrew) let them dry and further inspection showed no sign of the schmutz by finger or eye.
My conclusion is that the offending material was probably mold release that was not fully flushed out when the tanks where made and the whole affair is not related to Mo-Gas. I strongly recommend that if you have tanks of this vintage you run your finger inside them, any sense of stickiness/tackiness follow the procedure above, this stuff will stop your engine.

Back on track, looking for inspection next week.

Dorsal, glad to help... yours was the first Kitfox I have ever seen up close... what a beauty... the design is ingenious and your attention to detail and well-thought-out avionics program are A+. Can't wait to see you fly it...

PS, the acetone rinse was a smart solution... the Kitfox folks may want to add your fuel tank story to their "things to check before you install the tank in the wing" list...

PSS, I thought that the Kitfox build manual was second to none... the McBeans could teach the barbecue grill people a thing or two about how to put things together... ; )

Quote:

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My conclusion is that the offending material was probably mold release that was not fully flushed out when the tanks where made and the whole affair is not related to Mo-Gas.

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Dorsal. I'm not buying your conclusion and don't think you should proceed as if you've solved anything. Yet.

I developed no problems with any contamination during Phase 1 (40 plus hours of 100 LL use).
First fill of auto gas I used up in the same day. Next topping off with alcohol auto fuel sat in the tanks for 3-4 days. That's when damage was done. It turned the resign , not release agent, soft inside my tanks. After restoring both carbs , rinsing and going back to AV-gas I've had no recurrence and the tank resigns seemed to revert after rinsing and drying back to the correct state. I checked carefully and frequently. No leaks from the incident either. Luckily. Could your situation be different than mine. Maybe. But what if they are related? You may get airborne before it stops your engine this time.

I guess the only way to know is to repeat the process. Just be mentally prepared if the problem appears again. Keep Andrew close by. He knows the procedure now so no training required. ;)
Proceed with caution. I know you will.


P.S. Something else to think about during first flights.
I did find glass fibers in my fuel filters for about 15- 20 hours into the test flight phase. I watched this carefully as others advised me this could occur. I changed filters twice during my 2- 3 hours of ground runs(finding the most fibers during this period) and immediately prior to first flight. Then every 4-5 hours until fibers stopped showing up in the filter elements. Glass fibers are invisible when wetted with fuel so don't look at your see through filters and think you are safe because you don't visually see anything. Change your filters and inspect for glass fibers. After 700 plus hours I still remove, dry completely and then inspect my filter elements for glass fibers. Haven't found any since early into the test phase but can't help still looking.

DF4, First my conclusion still includes running AV-Gas but based more on your experience than this event (I do not want to repeat this process). I suspect from your description that these two situations do possibly represent different issues as the sticky stuff was present in my tanks before any fuel was put through them. At any rate we certainly got a bunch of schmutz out of the tanks that should not be there. Thanks for the reminder to replace and check the filter often, will do.

before i had put any gas in the original tanks , i removed the wings and sloshed both tanks with a epoxy . the epoxy i used is intended for repairing motorcycle gas tanks . like you dorsal , i had to do it with the tank installed also there is a limited working time with the epoxy . cant be too sure of how good the coverage is in the tank due to the baffles . i had approx 100 hrs on the airplane before i replaced one tank with a new mfg 13 gal tank . in fairness , i had used alcohol free gas and very little ethanol with no problems .

Dorsal,
I have "vintage tanks" in my aircraft and am waiting for the brown goo. I have been fortunate to have one gas station that still carries no ethanol but at the end of the year it is "curtains" ! The law mandates it in our state. Am holding off on the alcohol for as long as possible.
One other indication of a problem with that goo stuff is no compression as you turn the prop to burp your engine. The goo can coat the intake valve valve guides and stick the valves.
I have installed wing filters to check for flaking of the sloshing compound and I thought break down of the resin but I guess that won't work.
Am still thinking about the best solution if and when breakdown of the resin does occur. I probably will pull the wings remove the tanks and install the new ones that John offers..don't know yet.
Dick
912UL
Milton,Fl

I'm scared of brown goo or any goo in my gas so I recently removed my 1992 vintage tanks. I have been very fortunate to have non ethanol gas at my closest filling station but this is to end in Oct. I have never had ethanol in my tanks. Looking in my tanks revealed the kreem slosh starting to fall apart that prompted me to look inside closer with a scope. What I found was resin from the original lay up all over the inside of the tanks with large pieces broken off and floating around. This is only what I could see as there are two baffles. After much consideration I decided to go with the airdale tanks. These tanks are by no means perfect and have cons also, but I believe the are the lesser of the two evils.

there is no need to remove the wings, in fact leaving the wings on gives you a good working platform. I was able to do what was needed to remove the tanks and had a firm foundation on the wings to do so. If I had to do it again I would do the same. I ended up closing the wing part way to get to the hoses. In the end I ended up brushing on all the paint for I have a t hanger so many other airplanes where in a row. I didn't want paint getting into the other hangars. I need to put a couple more coats of paint on with one of those sponge brushes, after that I don't think you would be able to see where I did anything, came out real nice. I used polytone.

pretty considerate steve , i had a guy paint red paint on a navion with rattle cans next to my 170b and i ended up with red overspray all over my airplane . before i ever saw him again and could get sideways with him he had been hit in the head with the navion prop and killed himself . i ended up having to rub out most of the airplane to get it off .

i didnt have to worry about the guy , he took care of himself . all i had to do was clean off the overspray from my plane . im glad i wasnt at the airport the day he got smacked in the head .

Steve,
Could you please explain your method of removing the old tanks and replacing them ? I haven't yet explored how to do this and as I did not build the plane,I am somewhat unfamilliar with the layout of the wing.
Thanks !
Dick Maddux
Milton,Fl

catz , i didnt replace the tank like steve , i took the wing off, but there are some pictures in one of my albums of the inside of the wing . mine was a lot more work as i replaced a 6 gal tank with a 13 gal tank . it required removing a rib and relocating a brace . the one on the other side will go a lot faster when i replace it , i learned a lot doing this one .

Thanks Chuck,I will check it out
Dick