Improper starting procedure used
No fuel in gas tank - Add fuel. Don't assume the fuel gauge is working correctly.
Choke valve not closing sufficiently when cold - Realign the choke valve or linkage as necessary. If caused by dirt and gum, clean with automatic choke cleaner, or spray carb cleaner. DO NOT use oil to lubricate. Oil will collect dirt. If parts replaced re-adjust to specifications.
No fuel in carburetor - Remove the fuel link at the carburetor. Connect hose to fuel line and run into container. Remove the high tension coil wire from the center tower on distributor cap & ground. Crank the engine. If there is no fuel discharge from the fuel line, check for kinked or bent lines. Disconnect fuel line at the fuel tank and blow out the line. Reconnect the link and check again for fuel discharge. If none, replace fuel pump, then test the fuel pump for proper pressure. Most carburetors need around 4 lbs of pressure, but check your motors manual.The pressure varies greatly between carburetors.
NOTE: New fuel pumps are especially suspect. It isn't unusual for a new pump to put out too much pressure. Either get a pump that works correctly, or install a fuel regulator.
If fuel supply is OK check the following:
Inspect fuel filters. Replace if dirty.
Remove air horn, or fuel bowl and check for a bind in the float, or sticking float needle.
Vehicles that have been sitting may contain gas that has turned in varnish, coating the inside of the
Look down the carburetor after turning the engine off. Is the fuel dripping out of the venturi. If so check these things: