Here's my test procedure, which I've used for about 40 years. First, get enough fuel into the carb to keep the engine running for a short time, either by filling the float chamber through the bowl vent tube, or some other means. Use a gravity-feed small tank if necessary. Disconnect the fuel line from the carb, and run a rubber line into a catch container like a 2-liter Coke bottle or something similar. Use enough hose to keep the catch bottle away from any ignition source like the spark plug wires, etc. Start the engine, and idle for 30 seconds. You should get about a pint of fuel pumped into the catch bottle. If that check is OK, you probably don't have a fuel system poroblem. If not, and there's any flow at all, proceed to the next test, which is fuel pressure. Use a pressure gage that will read up ro about 10 pounds, and attach it securely to the carb inlet line. At idle, the pump should develop 4-5 pounds of pressure, and hold it for a short time after the engine is stopped. This checks the output check valve in the pump. Then go to the pump inlet fitting and attach a vacuum gage. Run the engine, or At least crank it, and you should get about 10" of vacuum from a good pump, and it should also hold the reading for a few seconds after the pump stops. This checks the inlet check valve. Good so far? Go to the tank outlet, and check vacuum at the line going toward the pump. Same, or at least slightly lower vacuum reading should be present at the tank. This checks the line for restrictions or holes. If all the above checks except volume are OK, the problem is a restriction inside the tank!
Jerry
