carb
You only need 2-3 lbs fuel pressure at the carb. I much prefer the mechanical fuel pump. It is cheaper, will last a long time, and can be rebuilt for very little. The old fashion fuel bowl can be replaced if it corrodes through or the bail rusts out. Sometimes the upper part can bend where the bowl fits causing a air leak, (might be your problem). An electric pump would not cure your problem unless the mechanical was bad. If you put on an electric and the mechanical diaphram is bad you will get gas in your oil unless you remove the mechanical then you need a blanking plate to keep the oil in the block. You also need an oil pressure switch that is normally open and closed when you build oil pressure. this is tied to the fuel pump so if the engine quits, the oil pressure drops and turns off your fuel pump. without that switch the pump runs when the key is on. big saftey issue. I rebuilt 3 carbs last week, one was mine. All 3 the float was out of adjustment. one had a corroded idle circuit, it was completely blocked. The customers complaint was it would not idle. He called me a few days later and told me it would idle so slow that sitting in the cockpit he was not sure it was running. SO. Check for air leaks in the fuel system from the tank to the carb. If the ignition is sound and the timing right I would go for the carb cleaning. There is a difference in cleaning the carb and rebuilding. This is a quality carb, the design is good. Sometimes you can get by with cleaning it. The decision is, is the gasket good enough to reuse. Is the float valve seat and needle in good shape. Do not soak the needle valve in cleaner as it has a rubber tip that can disolve. The choke and throttle shaft are steel and the aluminum body has steel bushings for the shafts so wear is minimal. It is not pumped all day like a car. These shafts do have rubber seals similiar to an oil seal to keep air out. If these seals are gone it can run lean and not idle. Also check the surface of the top and bottom half of the carb where it meets the gasket. These surfaces warp from screw pressure and cause air leaks. use a piece of glass or something flat with a piece of wet or dry sandpaper. a little oil and rub the mating surface of the carb accross it. You will soon see what I mean. Some people sell a rebuild kit by taking the standard zenith kit and adding jets to it and doubling the price. You do not need the jets, just clean them. about the idle screw location. take the below link and click on fuel. you can see a pic of a carb that shows the screw. It has a spring around it. it is right below the flange that bolts to the manifold on the right side. If you can not see it e-mail me and I will send you a big picture. will
