I know that there are many different specc'ed float heights, but more specifically, is there a "set" level of fuel in the bowl? Apart from dealing with the obvious safety issues with flammable liquids... why not disable the ignition, hold the float hinge arm down, and crank the engine (or turn on the electric pump) until the float shuts off, then measure the actual fuel level? (assuming the air horn is off, otherwise I suppose you could use a "dipstick" down the vent tube)
Interestingly enough, I worked at a shop in '76 after I got out of the Navy where the owner did just that. He held down the pivot that the float worked on and ran the engine to see if there was a problem with the needle and seat. Quite dangerous, if you think about it.
I wouldn't even try to run the engine, but I've cranked them (ignition disabled) with the air horn off to confirm needle / float operation.
James, its amazing that you posted this. I recently started a thread discussing fuel leaking from the carb and got great suggestions as replies. Yesterday, after making some adjustments to the float, I thought "Wouldn't it be nice if I could test it with fuel and watch what happens during cranking." So, I put an old towel on the intake manifold, set the carb on the towel, then connected the fuel line. But that's as far as I got because no one was here to turn the key while I pressed down on the float hanger. I plan to try it later today, when my son gets home. Great minds think alike. -Dennis
I've done this many times, using an electric pump so we don't have to run the engine. Fuel pressure, fuel inlet seat diameter, float size, hinge pin location, and float level all play a role in actual fuel level in the bowl. This is why I ALWAYS ask folks who contact me with carb issues, what rebuild kit they used. IF you used an over the counter kit, it will contain the incorrect fuel inlet seat, so you are already in trouble everywhere else. Fuel level in the bowl has a DIRECT impact on carb function, calibration, etc......Cliff
Difficult question, as fuel level is often related to the application in factory set-ups. Marine carburetors, for example, were often installed at greater angles than many automotive carburetors, and the factory used different float levels to put the fuel I the carb where they wanted it. Few set-ups will have the carb perfectly level, for a variety of reasons, so the actual fuel level will vary some application to application.....Cliff
