I am asking this question for my dad who owns a 1982 Ford F100 with the inline 6 with single barrel carb.The problem is the truck will quit running and the only way to fix it is to blow compressed air through the gas line coming from the tank.This has happened twice.Is there something in the tank that is broke or is it something else.The fuel pump was also just replaced because we thought that was the problem but its not, Other than this problem the truck runs perfect.

 

The screen on the pick-up tube in the tank may have crud on it. If it does, then the tank needs to be drained, dropped, and cleaned out. I've used two handfuls of round gravel, and a little bit of water, taped over the tank openings with duct tape, then roll the tank every which way across a lawn. Then emptied, flushed out real good with a garden hose, let dry in the sun.

Less likely is a tank venting problem, where air is not going in to replace fuel being used, but momentarily taking the gas cap off to equalize pressures would temporarily solve that, and should restart again.

 

My 82 L6 had similiar problems. The interior of the tank was full of rust. I had gone through a number of fuel pumps before I finally replaced all the rubber fuel lines, cleaned out the metal lines and put in a new tank. Runs great now. One of the problems is that the fuel filter is between the pump and carb. Any crud from the tank gets into the pump and ruins it in short order. I added a clear inline filter just before the fuel pump to trap any rust or crud before it got to the pump.

 

Torky2 said, "The screen on the pick-up tube in the tank may have crud on it."

Just last weekend, I was talking with a friend who is a Ford dealer mechanic. He started working in the mid 80's, when our trucks came along. He said that some of the "older" mechanics would take an air line and attach it to the fuel line coming from the tank and literally blow the screen off the fuel line while it was in the tank [without removing the tank]. They did this when there was a fuel delivery problem and the screen was suspected. Then they put an inline filter between the tank and fuel pump.

 

Old-time method of cleaning fuel tanks: drain, dump a gallon of Kerosene and a couple pounds of marbles in tank. Cap tank and put tank in back of another truck bed and drive on rough country road. Long drive! Patience is the key with this method. Adding a filter before the fuel pump is a good idea.