Fuel Pump vacuum question

[Screech]

My dad and I are trying to get my grandpa's 1968 F100 truck with a 360 CID engine started. I don't beleive it has ran in about 10 years, so we are trying to cyphen the old gas out of the tank so that fresh gas can be used. We first tried to cyphen it out connecting a hand pump to the fuel line in the engine bay on the discharge side of the fuel pump. Nothing would come out. So we took the whole tank out of the truck and are now pumping it out of the filler neck. Why were we unable to cyphen it using the fuel line? How does the gas line inside of the gas tank work? After disconnecting fuel line at the top of the tank, we were able to suck through the fuel line and also blow through the fuel line. The fuel line inside the tank appears to be completely plugged. Is there a way to clear the fuel line inside the tank. The fuel line inside the tank is welded to the top of the fuel tank so we cannot look at it to see how it works. Are any diagrams of this fuel line inside the tank available? Is there a valve or filter on this fuel line inside the tank that may be plugged?

Any help would be much appreciated.

Thanks
Kevin

[BobbyFord]

Get the tank cleaned and installed with fresh fuel, then fill the carburetor via the bowl vent or dump a little fuel down the carb and let the fuel pump draw the fuel from the tank. It may take a couple of tries before the fuel reaches the carb from the tank.

[Screech]

I think that either the valve or the line in the actual fuel tank is clogged. I'm just not sure how to clean this line or valve out. I would just cut it out of the tank, but it would probably blow up on me. haha. Anyone else ever had this problem or know how this can be fixed?

[BobbyFord]

If you think the tank line is plugged, while you have the tank out and clean blow compressed air through the tube. Likewise with the line from the tank to the fuel pump, just be sure to disconnect it at the pump first.

[HOWDY69]

We first tried to cyphen it out connecting a hand pump to the fuel line in the engine bay on the discharge side of the fuel pump. Nothing would come out. Why were we unable to cyphen it using the fuel line?

If you had disconnected the input side of the fuel pump, gas would have flowed out the hose. On the discharge side you were fighting the fuel pump.

How does the gas line inside of the gas tank work? After disconnecting fuel line at the top of the tank, we were able to suck through the fuel line and also blow through the fuel line. The fuel line inside the tank appears to be completely plugged. Is there a way to clear the fuel line inside the tank. The fuel line inside the tank is welded to the top of the fuel tank so we cannot look at it to see how it works. Are any diagrams of this fuel line inside the tank available? Is there a valve or filter on this fuel line inside the tank that may be plugged?

If you remove the sending unit you can shine a light down the filler and look in the sending unit hole. The gas line in the tank drops staight down to almost the bottom and then makes a slight bend. There was originally a filter sock on the bottom but most have long since dissolved. Other than the sock I have not heard of any other filter or valve.

These trucks are great to work on with only a few irritating things about them. Unfortunately the welded in drop tube in the fuel tank is one of them.

By the way...

[fordman]

i used a coat hanger and a air gun to clear my pickup tube out.

[Dragon]

When you tried to suck from the outlet side of the pump you sucked a one way valve closed.

[Screech]

Sorry for the confusion, we actually sucked from the inlet side of the fuel pump, not the discharge side. Thanks for all the comments guys. We will try these suggestions tomorrow and let yaw know how it turns out.

Thanks

[Dragon]

When you disconnected the inlet side gas should have just run out of the tank. I have something in my tank that is hiding from me. At below a 1/4 tank a right turn will send the gas to the left side and my truck will die a few feet later from fuel starvation. I have to disconnect the line from my electric fuel pump's inlet right under the tank and blow backward into the tank to clear it.

[Screech]

Alright guys, we fixed the gas problem. We used a coat hanger and air hose to clear the line in the tank. Then installed a new fuel filter and battery today. So now we have gas going to the motor. We found out we don't have spark though. I found the wiring diagram for the ignition system, so we're checking into that right now. We are going to try to bypass the ignition switch and see what happens. Any ideas would be great.

[fordman]

why are you looking at the ignition switch if it has no spark? i would check points and condensor as well as coil before i looked at the ignition switch. unless there is no power from the wiring. then i would find out where the power stops at and go from there. unless you have already figured out that the power stops at the ignition switch. then it could be a bad switch or the resistor wire is burned out so no power to give it spark.

the red and brown wire on the starter relay are hooked up and in the proper places arent they? red in front and brown in back? i did that once myself and it wouldn't start for anything. th red is the wire that goes to the switch though. the brown is a straight wire directly to the coil.

[HOWDY69]

If you want to check the switch, disconnect the positive wire to the coil. Put a volt meter between the positive coil wire and ground (like the exhaust manifold). You can use a 12 volt continuity tester light if you do not have a voltage meter. One of you can read the meter or view the light while the other turns the key to run and wiggles it. If the meter/light fluctuates when you wiggle the key you have a faulty switch. If the meter/light is steady you have power to the coil, move on to other components.

I use the trouble shooting charts in the Haynes manual to help me test systems in some reasonable order.

[Screech]

OK, we tested the voltage at the positive terminal on the coil and it reads 12 volts as it should. we still don't have spark at the plugs. The weird thing is that we cranked the motor yesterday and it ran for about 2 min. then shut off. Sometimes we will have spark and sometimes we won't. We also cleaned all the electrical connections and grounds. The ground wires are clean and still in good shape. What point gap clearance do we need on the ditrubuter? I searched and couldn't find anything.

Thanks

[fordman]

the point gap on a FE enigne is .017. did you loose the ground to your condensor inside of the distributor?

[Dragon]

Measure the open points voltage to ground inside of the distributor on the points moving arm with the points open. That will rule out the wiring from the battery to the points.