Topic: weeping carburetor


PeterFord    -- 07-30-2011 @ 3:07 PM
  I have a 51 Ford F1 pickup. I had a rebuilt carburetor put in a few months ago. The thing leaks gasoline very slightly, like a weeping. Clearly must come from a bad gasket. But they were all new. I have tightened all the mounting and connection bolts but it still shows gasoline on the engine block. Not a lot, but enough to worry me about a fire. I am considering getting a new carburetor from Dennis Carpenter. Have I exhausted all the possibilities? Or, do these carburetors always weep like this?


ford38v8    -- 07-30-2011 @ 4:34 PM
  Peter, be very careful about tightening the carb screws further. It is only cast alloy, and the screws will strip out easily. It is possible that although you have a rebuilt carb, it was set up with the float too high in the bowl, allowing overflow boil-out from the vent above the inlet. Another possibility is that the economizer valve is leaking, something that happens frequently due to the new fuel we are forced to use. A third cause would be that the check valve in the accelerator pump may in fact not be there at all, having been overlooked by the rebuilder. Fourth, the inlet line to the carb may not be fitted tightly. Fifth, last, and most obvious being a bad gasket.

Alan


PeterFord    -- 07-30-2011 @ 6:15 PM
  Alan:

Many thanks for your reply. I think I am going to order a new carburetor and be done with it. You have been most helpful.

Peter


supereal    -- 07-31-2011 @ 9:34 AM
  Quite often, seepage around a carb gasket is due to a warped gasket surface on one or both halves of the body. The pot metal won't tolerate overtightened fasteners, and bends enough to cause the problem when the gasket is compressed. We fix it by placing fine sandpaper or crocus cloth on a piece of glass, and scrub the gasket surface back and forth until no voids show. It isn't a tough job, and a whole lot cheaper than several hundred bucks for a new carb.



PeterFord    -- 07-31-2011 @ 1:32 PM
  what keeps the gasket level on the sandpaper/glass surface while you scrub it back and forth?

Peter


ford38v8    -- 07-31-2011 @ 2:25 PM
  Peder, the carb's mating surfaces need to be re-faced so the gasket will be effective. A flat surface like glass can be used with fine sandpaper on it to gently slide the carb face over, being careful that the carb remains flat against the surface while doing so. Upon inspection after just a couple of passes, you will see all imperfections in the flat surface that will need to be squared off. Caution, do not use the sandpaper by hand, but always by placing on that flat surface.

Alan


supereal    -- 07-31-2011 @ 4:29 PM
  I was referring to the gasket surface of the carb body, not the gasket, itself. My friend, Alan, covered the procedure. The glass is to assure an absolutely flat surface. Gasoline has a very low surface tension, and easily escapes very small places. Be sure your carb has alcohol resistant gaskets, of fuel will seep thru them.


TomO    -- 08-02-2011 @ 8:00 AM
  Peter,

It is not normal for the carburetor to weep or leak, and this condition should be fixed to prevent a fire.

A common place for carburetor gas leaks is the drain plugs. Make sure that the correct gaskets are used as the kit has some that look like they would work. The correct gasket just fits over the plug. Use a screwdriver with a blade wide enough to fill the slot and then tighten the plugs. From your description, this sounds like your problem.

The next common place is the power valve gasket. The power valve gasket is the one that is the exact size of the machined surface on the bottom of the carburetor. Tighten the power valve to a max of 15 ft lbs.

If you are leaking gas out of the top cover, the float is set too high. The fuel level should be 11/16" from the top of the bowl.

If your leak appears to be from some other part of the carburetor, please post where you see the leak and we will try to find a solution.

Tom


51f1    -- 08-17-2011 @ 12:47 PM
  The carburetor in my '51 F-1 was leaking from the float chamber, and, after a few days, it would not start until the float bowl was refilled. The leak wasn't apparent on the outside of the carburetor. I immediately thought of the power valve and took the carburetor apart to check it. It turns out that it wasn't the valve but one of the main jet access plugs (drain plug). It was weeping almost imperceptively. A little Permatex No. 3 on the threads fixed the problem.

By-the-way, I have never had a power valve with the gasket surface machined wrong, but y'all talk about that so much, I had to look and make sure that wasn't the problem. I have two of the valves, and both are correct.

Richard

This message was edited by 51f1 on 8-17-11 @ 12:48 PM


ford38v8    -- 08-17-2011 @ 5:31 PM
  Richard, your permatex fix should not have been required, as there is supposed to be a gasket on those plugs. Perhaps it had been damaged and wasn't sealing correctly?

If you have two power valves, you must have a very special carburetor!

Alan


51f1    -- 08-26-2011 @ 6:42 AM
  My carburetor is a NOS carburetor that never leaked before. When I installed it almost 20-years ago (its actually only been used about 4 years), I put a kit in it. I recently put another kit in when I restored my truck to be sure that there was nothing in it incompatible with modern gasoline. After installing the new kit it would leak down in a few days (the float bowl would be about empty) so I took it apart to look at the power valve. The valve looked O.K., so I filled the bowl with gasoline and let it sit a while. After sitting, the the right hand nozzle access plug was damp with fuel. The power valve was dry. The gasket on the plug was new, and I probably could have tightened it to stop the leak, but I used Permatex No. 3 as an added precaution. Anyway, it doesn't leak anymore.

I only use one power valve at the time. What I was trying to convey is that I have never found a power valve in a rebuild kit that was machined improperly.

Richard

This message was edited by 51f1 on 8-26-11 @ 6:43 AM


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