I've replaced my fuel pump on my 64 223. Slid it in place and bolted it down easy. Got the right fuel lines hooked up to the right spots. My question is, if it slides in am I good? Or is there a trick to get the arm to engage? My truck has always been slow at getting fuel back through the lines but I just want to make sure I'm not missing something before i give it another go tomorrow morning. I cranked it quite a bit today and the filter didnt even fill up (which I double checked to make sure it was going the right direction. When I had the line off the pump, it was dripping gas so I know gas is making it to the pump. Thanks for your help!

 

Fuel pumps are usually straight forward and are driven by a cam lob that hits the arm on the pump.

Last summer I replaced the section fuel line right under the tank and was surprised the system did not have the gravity feed I suspected. I am not sure how the lines function in connection with the fuel tank. There must be a line in the tank because the feed comes out the top; the tank is not an obvious gravity feed.

Hopefully someone on the forum can explain how the gas tank hook ups and lines work on a tank behind the seat on a 1966-- 240 which I have.

Normally I would say you can always blow compressed air back into the line to check for a plugged up tank, but behind the seat gas tanks are different, so I hope some chimes in to explain. One other approach would be to prime the carb and strait the truck that way and see if that creates a vacuum and pulls fuel up and out.

Steve

 

Apparently your lines have debris in them or the pickup tube in the tank is blocked off some. I would blow through the lines from the pump back through the tank. That should give you an idea if what is happening.

 

This will probably sound crazy but the mechnical pumps are so efficient that I have always had good luck just operating them by hand to draw gas from the tank. Provided they are working well it should create all the vacuum in the line needed to create a siphon effect.

The tube starts down inside of the tank as a separate tube with fitting at the top of the tank. That internal tube connects to the external tube on top of the tank. The external tube is the one that runs horizontal to the top of the tank toward the filler neck and then down through the floorboard grommet to the frame area. Since this lower portion of this external tube is below the lowest level of the gas tank it will allow a siphon - once started - to practically drain the tank. We've seen cases where the internal tube in the tank develops enough perforation (rust holes typically) that a siphon can't be accomplished.

So, first test is to grab a bucket and put it under the cab below the external line ending and hook a short piece of rubber hose to that and see if you can get a good siphon going. If not then there is likely a problem in the tank. If you can get a siphon going then save the gas into the bucket. This step also primes the line out of the cab.

From under the cab there is a short section of rubber tube before it turns to metal again from below the tank going up front to the fuel pump. Optionally you can try to start the siphon at this point. Remove the rubber line from the fuel pump and draw on the line going to the tank and it should start a siphon there. Keep the rubber hose below the level of the bottom of the tank and make sure you have enough gas in your tank to reach the internal pick up tube otherwise you'll be spinning your wheels. Blowing compressed air into the tank can open up a line if it is plugged but making sure you remove the gas cap before attempting that might be a good idea.

If you can't get that siphon going I wouldn't even focus on the pump right now since the issue would be upstream of the pump.

 

You aren't missing anything regarding install. Just make sure it slides in easily and isn't caught on anything. Regarding the fuel line, because the tank is higher than the pump, you should be able to easily draw fuel through the line before it meets the pump. Obviously not recommended but I checked/primed by sucking gas from the end of the inlet. It arrived fairly quickly. You can always disconnect the fuel line from the carb, disconnect the coil, and crank the engine to see fuel flow. It should spurt quickly and what seems like a lot of fuel. Outside of that there are fuel pressure tests you can do, but use your senses and you should be good.

 

I've been giving it a go this morning with bad results. If I take the fuel line going into the pump off I get no flow. If i suck on the line a bit, I get flow so I then reconnect to the fuel pump, spray some starter fluid in the carb and the truck turns over for a sec then dies. I check the filter and its empty again. I pull the gas line off the fuel pump and again, no flow. I suck it through and it flows fine again. I tried that three times with no luck. The only difference (aside from the new fuel pump) thats different from yesterday is that I added some gas line right before the FP to give it more slack. Any ideas?

 

This is what I would do. Get a gallon jug with a quart or two of gas in it. Run a suction line from the pump into it. Fire it up. If it runs your problem is in the lines, if it doesn't you may have a bad pump or the cam that operates it is worn out. Not likely but possible.
Also make sure you got it hooked up right. Don't laugh it's easy to connect the lines to the wrong fitting.

 

I figured it out. I took the pump out to see if it was even working and realized I had the lines backwards. What a jackass. Thanks for your support everyone!

 

The good news is you fixed it and got an education. Experience is the teacher synthesized knowledge will show up down the road on your next problem. life is solving problems ---plus I was always curious about how those gas tanks worked. He that does not maketh mistakes does not learnth. No jackass here or there.

steve