Help me figure this out
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Trailering
Joined: Nov 2019
Posts: 16
Likes: 1
Help me figure this out
I am getting no fuel to the carb on my truck.
. I have a 1970 f100 4x4 with a 4.9 in it. New Carb New Fuel pump. I pulled the tank out and made sure it was clean and the pick up was clear but no matter what I do it won't start or run. My mechanic friends never show up to help like they promise they will. So I am doing all this on my own
. I have a 1970 f100 4x4 with a 4.9 in it. New Carb New Fuel pump. I pulled the tank out and made sure it was clean and the pick up was clear but no matter what I do it won't start or run. My mechanic friends never show up to help like they promise they will. So I am doing all this on my own
FTE Legend
Joined: Nov 2015
Posts: 30,912
Likes: 4,123
From: Angier, NC
I had a issue where I could not pull fuel from a can sitting on the inner fender so I installed a new fuel pump.
Guess what ........... still would not pull fuel from the can.
What I found was the rubber hose I was using from pump to can was the wrong size and even with 2 clamps think it was pulling air.
My truck uses 5/16" hose and I was using 3/8".
Now with that said make sure you used the right size hose from tank to hard line and hard line to pump.
To test the pump get a gas can and hose and set the can in the engine bay and the hose into the can.
Pour a little gas down carb and see if it will run on the can of gas.
Also how much gas did you put in the tank to see if it would run?
Maybe add more gas to the tank.
Dave -----
Guess what ........... still would not pull fuel from the can.
What I found was the rubber hose I was using from pump to can was the wrong size and even with 2 clamps think it was pulling air.
My truck uses 5/16" hose and I was using 3/8".
Now with that said make sure you used the right size hose from tank to hard line and hard line to pump.
To test the pump get a gas can and hose and set the can in the engine bay and the hose into the can.
Pour a little gas down carb and see if it will run on the can of gas.
Also how much gas did you put in the tank to see if it would run?
Maybe add more gas to the tank.
Dave -----
Tuned
Joined: May 2009
Posts: 301
Likes: 40
From: East Tennessee
Be sure to replace all the rubber hose, including the short piece under the driver's door where the line from the cab meets the line from the engine bay. Old rubber and ethanol don't go well together. Since you have a 70, the hose should be 3/8 from tank to fuel pump I believe (67-69 used 5/16). Between the fuel pump and carb it's probably 5/16.
Where'd you get your fuel pump? Napa sells Carter pumps that are good. The made in china ones are junk. My 240 loves the Napa pump it has now. My problem was the Chinese ones were flooding my Carter YFA carb, so we had somewhat different problems.
Where'd you get your fuel pump? Napa sells Carter pumps that are good. The made in china ones are junk. My 240 loves the Napa pump it has now. My problem was the Chinese ones were flooding my Carter YFA carb, so we had somewhat different problems.
Tuned
Joined: Oct 2014
Posts: 419
Likes: 7
From: Rimrock, AZ
If the lines are empty sometimes it can be a bit hard to get it to start feeding. Assuming your fuel pump is good and lines are clear I have previously taken some compressed air on the filler neck and made a seal with my hand, put some pressure in the tank while someone else cranked and had success. You can also use some starting fluid and keep it running for about 10-15 seconds and you should have fuel pumping by then. If not, you have a problem in the pickup, lines, or filter. Fortunately there isn't many parts between the tank and the carb so finding the problem should be fairly easy.
Lead Driver
Joined: Jul 2017
Posts: 9,600
Likes: 1,174
From: San Jose, CA
What they all said.
Even in the good old days when you could get a fuel pumps that worked, they didn’t always have enough suction to start the prime without a little help.
There are different ways to prime a pump, but one of the easiest is to do what was suggested and get fuel into the carburetor first.
Once the engine starts up and is it operating speed a decent pump will usually pull hard enough to get the fuel flow started into the lines.
Rather than putting gas down the throat of the carburetor though, try to get it into the float bowls so the engine will run for a while. .
Anytime you use starting fluid or just pour some gas down the throat it’ll only run for a few seconds at a time and that’s not always enough.
Filling the float bowl can give you at least a couple of minutes of run time.
Good luck.
Even in the good old days when you could get a fuel pumps that worked, they didn’t always have enough suction to start the prime without a little help.
There are different ways to prime a pump, but one of the easiest is to do what was suggested and get fuel into the carburetor first.
Once the engine starts up and is it operating speed a decent pump will usually pull hard enough to get the fuel flow started into the lines.
Rather than putting gas down the throat of the carburetor though, try to get it into the float bowls so the engine will run for a while. .
Anytime you use starting fluid or just pour some gas down the throat it’ll only run for a few seconds at a time and that’s not always enough.
Filling the float bowl can give you at least a couple of minutes of run time.
Good luck.
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