How to Troubleshoot No Fuel Going to a Carburetor

No fuel at your carburetor can be caused by many things. It could be a simple issue like a fuel filter plugged so tight that no fuel can pass through. Another logical cause could be the fuel pump. If the fuel pump is electric, the 12-volt power may be shorted. A hole in the fuel line on the tank side could also cause the fuel pump to suck air instead of fuel from the fuel tank. There may not even be signs of leaking, since a fuel line leak on the tank side would have to be above the fuel level for leakage to show.

Things You'll Need:

• Safety glasses
• Wrench set
• Screwdriver set
• Fuel pressure gauge
• Fuel hose

1. Remove and check all fuel filters located in the fuel line and in the carburetor

Remove and check all fuel filters located in the fuel line and in the carburetor. Replace any and all filters that can not be confirmed good or have not been changed recently.

2. Inspect the fuel lines for leaks or kinks

Inspect the fuel lines for leaks or kinks that might interfere with fuel flow.

3. Tap the top of the carburetor lightly to free a stuck needle valve or float

Tap the top of the carburetor lightly to free a stuck needle valve or float that may be shutting off fuel to the carburetor float bowl.

4. Check the fuse marked fuel pump in the fuse box

Check the fuse marked fuel pump in the fuse box for any electric fuel pump equipped vehicles.

5. Connect a fuel pressure gauge to the Shrader valve

Connect a fuel pressure gauge to the Shrader valve if the vehicle has an electric fuel pump. Turn on the key and monitor the fuel pressure, it should be around 60-psi. If equipped with a mechanical fuel pump, remove the fuel line to the carburetor and connect a fuel gauge to the fuel pump. This should yield a low pressure, under 20-psi when the engine is cranked over.

6. Check the mechanical fuel pump

Check the mechanical fuel pump by placing a fuel line into a gas can and attach the other end to the intake of the fuel pump. Crank the engine and check for fuel at the carburetor. The engine may start with fuel from a remote source such as a fuel can. If the pump draws fuel from the can and not the tank the tank screen must be inspected and or replaced. This would require removing the gas tank.

Tips and Warnings

A Shrader valve looks like an air valve on a tire used to add air to a tire. See the specific service manual for the exact location.

Visit an auto parts store, have the clerk look up the location of all fuel filters specific to the vehicle under repair.

Always wear eye protection when working on or around vehicles. Fuel is a combustible, handle fuel with care. Fuel is an known irritant, avoid contact with skin. Removing a fuel tank can be dangerous, great care must be taken to do it safely.

Video: How To Fix Your Fuel System When The Carburetor isn't getting Gas

Helpful comments on this video:

• Great video! I recently replaced the carburetor on my 67 F100. The previous owner had that belief that bigger was better and had a Holley 750 on an almost stock 352 FE. I replaced it with a more street-able Holley 600 cfm with a vacuum secondary.
  When the swap was done, I was experiencing a very strange phenomenon... the pump would put fuel into the bowl, then suck it back out.... I went through the carb thinking it had to be the floats sticking or something similar on an out of the box brand new carb...
  Come to find out, MY 67 F100 (with the factory tank behind the seat) has no vent. I had replaced the cap a day before the swap with a new OEM style fuel cap, and the new seal did its job. This caused a the tank to have a negative pressure and was pulling any fuel the pump put in the carb back out. I removed the gas cap, after wrestling with the carb for a day or two, and turned the key and it fired right up.
• Great episode! And, yes, i always put a clear filter immediately after the sending unit for just such reasons. Cheap insurance and one more layer of cleanliness.