71 Duster 318 fuel pump not pulling fuel from new gas tank

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Ken71Twister

Ken71Twister

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I just installed a new gas tank and in-line fuel filter. I re-installed my old sending unit because it tested good (and new one didn’t). I cleaned the carb and installed a new (transparent) gas filter. I‘m starting off with no fuel in lines, filter, or fuel pump because I let the engine run dry after I’d emptied the gas tank.

I added 5 gallons of gas to the tank and cranked the engine several times. There’s no fuel coming into the filter. The filter walls are clear and just ahead of the fuel pump - so I can see that the filter is empty.

I blew thru the air vent to make sure I hadn’t reversed the hoses coming out of the tank. Seemed OK.

Any suggestions? I don’t think the pump needs to be primed. What are the odds that the pump (original mechanical type) went bad for the 7 days that it was empty?.
 
Are you sure the sender lock ring is fully seated? Some of the after market rings are thinner than OEM.
 
I won’t know if the lock ring is good ‘till I get more gas in the tank. Either way - the fuel pickup line should be submerged with 5 gallons in the tank. For the record - the lock ring was very unsatisfactory because the diameter is too small to center reliably. I actually had to pull the tank off part way thru the re-install because I could see that the lock ring wasn’t secure. The second time, I carefully centered it so all three lock tabs were engaged - but it should have a larger diameter to not allow the ring to only engage 2 of the 3 tabs if not carefully centered.
 
The after market lock rings are "thinner" not smaller than the OEM pieces.
 
Ken71Twister said:
I just installed a new gas tank and in-line fuel filter. I re-installed my old sending unit because it tested good (and new one didn’t). I cleaned the carb and installed a new (transparent) gas filter. I‘m starting off with no fuel in lines, filter, or fuel pump because I let the engine run dry after I’d emptied the gas tank.

I added 5 gallons of gas to the tank and cranked the engine several times. There’s no fuel coming into the filter. The filter walls are clear and just ahead of the fuel pump - so I can see that the filter is empty.

I blew thru the air vent to make sure I hadn’t reversed the hoses coming out of the tank. Seemed OK.

Any suggestions? I don’t think the pump needs to be primed. What are the odds that the pump (original mechanical type) went bad for the 7 days that it was empty?.
Click to expand...
It takes a bit for the pump to draw all the air out of the lines, give it a chance- it'll take more than just "cranking it several times". After all, it's a fuel pump, not an air pump.
Prime the carburetor; squirt fuel down the bowl vent tubes until the bowls are full. Then fire the engine up. You should have fuel in your filter before the carb runs dry.
Alternatively, if you still suspect a faulty fuel pump, disconnect the fuel pump from the supply line and connect a length of fuel hose to the pump. Put the other end of the hose into a full gas can, fire the engine up. If it's drawing fuel from the can alright, then your issue is in the lines or the tank. Make sure you didn't kink any metal lines when you pulled the tank, make sure any rubber hoses did not get bent into too tight of a curve so that it is pinched closed and is restricting or blocking flow.
 
Remove the fuel line at the pick up & blow through the p/up. You should hear gurgling if the p/up is submerged. No noise means the p/up is not covered with fuel.....
 
Possible the check valves in the pump have dirt in them. I would try hand priming the carb, depending on carb. If it has an accessible vent, use a syringe/ bulb, etc to squirt some fuel into the vent. You can fill the bowl, and engine should run, probably on just one fill, long enough to prime the pump. You have one of those hand pump vacuum testers? You can pull a vacuum on the fuel line disconnected at the carb.

Or just throw about a tablespoon of fuel down the carb throat and fire for the few seconds it will run. I would not think you'd have to repeat that more than 2-3 times

You should NOT have to do either. A clear/ clean fuel delivery line and a good working pump should prime. It might take some cranking.

Also, are you certain the connecting hoses, at the tank, line to pump, etc, are not crimped/ soft/ collapsing?

Are you sure there are no line leaks, loose clamps, mis-sized hose to line, etc?
 
AND NOW YET ANOTHER annoying story from the old days. In my days at NAS Miramar, 70-74, I held a part time job at the base auto hobby shop. A then friend had swapped a 396 into a 57 Chev. I had helped him assemble the engine, install the cam, and adjust the lifters. I KNEW that engine would fire. One Sat, I was not working at the shop, but rather on my own stuff. He came over 2-3-4 times through the morning, wanting to borrow a coil, etc etc, and finally says, "I really need your help." So I go out there, and there is the peanut crowd, and the owner, all swilling sodas. He hands me a can and says "We've been using this down the carb, it doesn't have fuel up from the tank yet."I smelled the can and handed it back and said, "go get me some gas in this can!!!"

It had kerosene/ JP- in it and they had been attempting to fire that new engine on that!!
 
Thanks to all for the suggestions. I look forward to getting out tomorrow to investigate further. The failure to start happened right at sundown…too late to do much plus I knew the starter and battery needed a break. I ran out of gas a couple of years ago and it seemed to crank up in just a few seconds with 5 gallons of gas added.
 
It takes a long time to get gas to the carburetor from a dry system. Here's what I do. Remove the gas cap and apply a small amount of shop air to the filler. Just use a shop rag to seal the air blower best you can. Do this several times. You can tell when you get gas since you have a clear filter. Just do it gently, as you don't want to over pressure and hurt anything. I always turn my regulator down to about 10psi. You don't have to do that if you're careful.
 
I disconnect the fuel line to carb and suck on it with a mityvac. Full pump and filter in 30 seconds, and a clear filter so I know when to stop.
Mouth works too and I know exactly what gas tastes like
 
65TerrorCuda said:
I disconnect the fuel line to carb and suck on it with a mityvac. Full pump and filter in 30 seconds, and a clear filter so I know when to stop.
Mouth works too and I know exactly what gas tastes like
Click to expand...
That works good, too.
 
Did a bee build a mud nest inside the pick up tube I had one build one in the oil pressure sender hole on my 340 sitting on a engine Stan and covered with plastic now its in parts getting the block cleaned out
 
Mystery solved. Bottom line - I screwed up. When I removed the old tank last week I made tags and marked the gas and air vent lines. Unfortunately - I somehow got them reversed. I reversed the lines this afternoon and then the car started easily. I did a lot of huffing and puffing on lines before I figured it out and I got a good taste of gas in the process. :-( I blew on the gas line under the hood and fuel came out of the air vent line under the hood. That was quite a surprise but it made the problem clear.
 
I just had this happen for the first time I couldn't get it to pull fuel, I sucked fuel up and got it flowing from the line and shoved it into pump. Been fine ever since.
 
I agree with priming the carb, fire the engine a few times the lines will prime up fairly quick. Good luck.
 
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