Fuel Supply System - Check Points Beyond the Fuel Pump

[Jason Edge]

Incredibly, in 3 days I have had 3 people ask about replacing their fuel pump or even adding an electric fuel pump because there carb is not getting gas.  It has gotten to the point I have copied and pasted the general responses seen below and thought it is worth sharing. 

One of the comments I have made is if you have not confirmed these other problem areas and instead just resolve to replace the fuel pump or add/replace with an electric fuel pump it could be like adding an electric fan to a leaking radiator to prevent overheating! 

Here is my list of areas to check beyond the fuel pump:

- Check from Gas Tank to Carburetor
I would check the entire fuel delivery line from the gas tank to the carburetor as follows.  AC equipped cars also have a vapor return line that is slight smaller than the fuel supply line. I would check both lines while checking as both can cause problems if leaking or clogged.

- Is the fuel sending unit good? They have a sock with a filter that almost always breaks apart after 60+ years letting debris move into the fuel line and clog things up.  This can be the hardest item to check as it requires dropping the tank and would leave this for last. 

- Are the short rubber fuel lines at rear from sending unit to the metal lines that run down the right passenger side of the car in good condition?  (i.e. have they been replaced in the last 20 years!)  These rubber lines become dry, brittle and get hair line cracks…then they eventually break. With the hairline cracks they have a siphoning affect. Like sucking soda from a glass with a straw with hole in the side. I would never drive a car period without replacing these 60+ year old hoses.  The rubber hoses a the front often get replaced several time but those out of sight & out of mind rubber hoses at over the rear axle on right side often go neglected.

 - How are that metal lines? Good and solid or is the metal thin and compromised. They can become paper thin and start to gradually leak. Since gasoline evaporates it can be hard to spot at first. 

- Next look at the the rubber hoses from metal line on to the fuel pump (and filter if AC car with vapor return line). Same issues as the rear rubber hoses.

 - Are clamps good and tight at all the connection points?  If not, you will get that siphoning affect and leaking.

- Fuel filter good?  The older original sponge and the newer paper element filters can physically start to deteriorate and disintegrate. If in doubt, install a new filter. 

- Is the carburetor inlet fitting Screen Clogged or worse Missing?  Where the metal line from fuel filter to carb attached to the carb, there is first a fitting that it screws into. Inside there is a metal screen. It is the last line of defense for the carb.  This is great, but you cannot see what is in there unless you disconnect the metal line and remove the fitting.  Like the rear rubber lines, this is an out of sight out of mind and overlooked component of the fuel delivery system. It should be clear of debris. 

 So, there over a ½ dozen areas that can stop fuel delivery regardless of condition of fuel pump.    One of the first things I always suggest that people do when they get these cars is go ahead and replace the rubber hoses with new fuel grade rubber hoses and can the inlet screen at carb. These are 10 minute checks each that can save you a lot of time and money. 

I will probably post this to our Help Page, maybe add more to it and inserts some pictures for reference and include in as a Tech Tip in upcoming newsletter.