Dripping Stromberg Carburetor...

[CptKelly]

Gails new engine has started dripping fuel. Over a period of time, even though its not all that visible, it leaks quite a bunch. The old Marvel carburetor on the C-85 I removed, did not leak at all. Why do the Stromberg's leak so much. I have seen many others that leak too. Don Sword said that it had a new steel needle in it, but it sure does leak. What is the fix?

Mike

[Roger Anderson]

Some opinions say that every Stromberg carb, with the metal needle, can be eventually made to stop leaking. There are other opinions that say some persons have made it a lifetime project of trying to stop them from leaking, some with success and others with failure. Mine leaks and so do many others. I just always remember to shut off the fuel after each flight. Part of having a Stromberg, I guess.

[Mikek]

Gails new engine has started dripping fuel. Over a period of time, even though its not all that visible, it leaks quite a bunch. The old Marvel carburetor on the C-85 I removed, did not leak at all. Why do the Stromberg's leak so much. I have seen many others that leak too. Don Sword said that it had a new steel needle in it, but it sure does leak. What is the fix?

Mike

Next time turn fuel on and if it drips open cowl and with a wooden handle, tap the side of the car at the bowl, see if it stops. Might be the float sticking, also might just have some dirt between the needle and set.

also like others have posted shut of the fuel if your valve works.

Mike K

[gusc]

Like the others say, mine leaks but I shut off the valve. It should be shut off anyway.

The problem that then may come up is a leaky shutoff valve, then you definitely have to do something!!

[Nathan K. Hammond]

What is the fix?

You can try to re-lap the steel needle or change it for a neoprene needle. Either is a 50/50 chance of success.

Why not put the Marvel back on?

nkh

[WWhunter]

I had a similar problem on my carb when I bought the Champ. The carb had just been rebuilt and I kept thinking it had to be the needle/seat. Well, it ended up being the NEW float had absorbed enough fuel that it would not float high enough to close the needle when it sat in the three-point attitude. If the tail was up any it didn't leak. Precision sent me a new float free of charge. Apparantly they had this problem with several floats.
Keith

[skyking3286]

I wouldn't put a neoprene needle in the carb, since they swell with some of the gasoline mixes out there. I took one out and it was in bad shape in my carb. They had a Delpron {(sp?) plastic needle but that is out of production. Steel looks like what we are stuck with for the rest of the life of the airplanes.

[Tim Juhl]

Strombergs tend to leak. I always turn the fuel off and run the engine a bit before switching it off.

On the F-AA list there has been discussion in the past of ways to lap the steel needle into the valve seat to stop the leaking so you might want to do a search. That said, if you determine that the float is OK I wouldn't drive yourself nuts trying to stop the drip - just turn off the fuel valve.

Tim

[WWhunter]

Mike,
Just wondering if you found the problem.

[CptKelly]

What I've been doing is to just turn the fuel off when I hangar the Champ. Don Sword said to take the carburetor off and send it to him, but I really don't feel comfortable doing that. I have flown the Champ a few hours since the dripping started, and there is no problem with the engine when you run it. It will still drip, however, if you leave the fuel on. I sure wish Don had used the Marvel carburetor that was on the old 85, it never dripped. Someone told me that the marvel made more power than a stromberg.. anyone out there care to comment on that?

Mike

[MikeB]

Mike,
I've never done it but I had a old (well, at that time) A & P tell me he lapped the needle to the seat using 'toothpaste'. I'm assuming he was talking about a steel needle. I 'd hate to keep turning the fuel on and off as pretty soon the tank valve starts leaking or the universal joint and pins wear out. I'm sure there are better compounds than toothpaste for light lapping, though. Just my 2 cents worth.

Mike Berg

[Captgrumps]

Mike

Toothpaste works. Had an "oldtimer" show me that too. About 50 years ago. It was cheaper than real store bought stuff.

Doug

[SFC Hiatt]

Had an "oldtimer" show me that too.....
Doug

Grumps you had an "oldtimer" tell you something...........was it Adam or Jesus......

Kidding of course.............without the "oldtimers" around my airport I would be setting on the ground wishing I was flying.....

[Tim Juhl]

I remembered what they used for a lapping compound...Mayonaise! Follow the link below for an interesting discussion.

Tim

http://www.bowersflybaby.com/tech/strom ... edles1.pdf