Failure of the engine to function is rarely caused by a defective carburetor. If the carburetor is determined to be the culprit (ie the ignition system is working properly and fuel is reaching the carburetor), the carburetor may be clogged or the float level may not be set correctly. The only adjustments the shade tree mechanic can make to the carburetor are adjustments to idle speed, idle mixture, choke control mechanism, and accelerator pump. Improper adjustment should not prevent engine operation, but proper adjustment is necessary for maximum operating efficiency. Let’s face it, the WWII jeep isn’t the most efficient vehicle to start with, so anything we can do to help is great.
connections
Check for leaks at the fuel line connections. If any leakage cannot be stopped by pulling on the union nut, there may be a split tube or a bad fit in the union. A damaged flare must be cut out and a new flare made with a flare tool. Packaging with a rope can serve as a temporary “field” repair. If the fuel contains a dye, a fuel leak can be indicated by a buildup of the dye. But it should be remembered that the porous metal used for some foundries sometimes allows a little seepage, and dye buildup may be due to this rather than a fuel leak. The leak may be due to a split adapter, in which case a temporary repair can be made by welding. NOTE: Be careful when trying to sell anything used in the fuel system. Parts must be cleaned of all fuel residue before attempting to weld. If you don’t know how to sell yet, just buy new parts!
fuel bowl
Fuel leaking around the fuel container cap indicates a loose cap, a damaged gasket or casting, or a faulty float valve. The slight leak is probably due to a loose cover. An extensive leak is likely due to a faulty float valve. NOTE: “Bad float valve” could simply be the result of contaminated fuel – dirt/rust etc.
Remove the fuel container cap to examine the float. If the float contains fuel, causing it to lose buoyancy, determine where the fuel entered the float and drill a small hole (1/8 in.) at this point. Drain the fuel from the float and repair the hole with a light bead of solder. NOTE: See previous comment on soldering. Today it is practical to simply get a new float in a carb rebuild kit.
If the float needle valve and seat show signs of wear, replace them with new parts and gaskets. From the carburetor specifications, adjust the carburetor, determine the correct float level, and secure the float by bending the float support arm. Hold the float in the closed position and blow into the fuel line adapter. No air should pass through the valve. NOTE: For Willys MB and Ford GPW carburetors, set float with a gauge or 3/8 in.
Examine the board. Replace it if there are cracks or hardened sections. Make sure the new gasket does not block any openings in the housings. Back out the cover screws evenly.
socket covers
Inspect all caps covering check valves and spouts. Tighten any of these that are leaking. Loose flange nuts will affect performance. Tighten the flange nuts that hold the carburetor to the manifold assembly.
fuel stain
Remove the fuel strainer cap from the strainer. Wash the strainer with cleaning fluid and a brush and dry with compressed air. Examine the strainer gasket and replace it if it is compressed or damaged. You can also replace the contents of the fuel strainer with a modern filter. Kits are sold by various WW2 jeep parts suppliers.