So, I am driving along in my 76 F250 with its original 460 and 4bbl carb. Suddenly the truck quits running and we coast to a stop. I am able to crank for a while and it finally starts again, but only runs for a few seconds, then stalls. We get out to take a look see. We take off the air cleaner cover and crank it up again. It runs for a few seconds then stalls. This time, since we can see the carb, gasoline spews out of the two little oran pipe looking tubes on the front of the carb all over the place. It does this every time now. Will only run for a few seconds, then its "Old Faithful Geyser" again!

What has happened to my otherwise great runnig truck?!? And how do I fix it?!?

 

For diagnostic purposes, it would help to know the fuel pressure the carb is getting. After you get it home, suggest you rig a fuel pressure gauge on a "T" on the feed to the carb. Fire it up and have a helper watch the gauge.

With a Ford (or Holly) carb, 5-7 psi is good, 9 psi is probably OK and more is a problem. FWIW Edelbrock carbs like 3-5 psi and over 5 is a problem.

If fuel pressure is OK, sounds like time for a carb rebuild, new carb or reman carb. Personally, I don't work on carbs enough to be good at it so I buy new or reman.

If fuel pressure is high, the fuel pump is hurting. Also check oil for signs of dilution from fuel.

 

Stuck/misadjusted float.
​​​

 

Depending on where you live, perhaps the fuel chemistry (ethanol?) is having it's way with your needle tip. Especially if you have one of the rubber-tipped type (or whatever that material is?) vs the brass tip type.

An old-school (but effective temporarily) trick is to smack the top of the carburetor near the float pivot to see if the issue goes away.
When I've experienced it, different carbs acted differently. Sometimes they would stick closed and starve the engine for fuel. Sometimes they would stick open and fill the float bowls like you're experiencing.
In both cases a good smack with an appropriate tool would get me back on the road again. For anywhere from a few months, to just a few hours at it's worst.

The tool of choice for me at first was the plastic handle on one of my bigger screwdrivers. Could get a good whack out of it without marring the carb body. But after enough time and still having the problem, I graduated to a hammer. At that point I just didn't care about the carb any longer!
Hope you don't get to that point.

Good luck.

Paul

 

I experienced the exact same problem in the yellow truck a while back. I was coming home from work, and when a Chevy pulled alongside at a red light, I was obliged to let the ponies run.

As I coasted to the next red light, I didn't notice that the engine died. The engine restarted, but then died again. I could only keep the engine running by keeping the RPMs way up, so I was driving home in first gear at 2000 RPM.

I pulled off to the side of the road, pulled the air cleaner, and saw the fountain. Some debris had either prevented the needle valve from closing or caused the float to stick.

Pulled the carb, pulled the bowls, blew everything out, and all was well again

 

Gentlemen,

Thank you so much for the advise! Sure enough, a few taps of the handle side of a screwdriver fixed the trouble. Simply hilarious.

A day before the bowls flooded over, I changed the fuel filters. I would say that I lodged something loose in the lines and it made it's way up to the bowl float valves and they stuck open.

On the road again!

Thanks.

 

Hey, congrats! Rollin' old-school baby!

Remember, if you can't fix it with a hammer, you have an electrical problem.
Then again, many a starter has been "fixed" with a hammer. And now you know you can fix a carburetor too.

Paul

 

Your scenario sounds like a likely one. Probably the crud was dislodged from the needle/seat by your tapping and landed in the bottom of the float bowl. If you ever feel like doing an overhaul of the carburetor, such is possible. I have the exact vehicle, and did the overhaul this past year. The carburetor is the Motorcraft 4350. The exact model is shown on a tag on the carburetor. Kits are available. If you'd like to read about it look in the Ford Truck Shop Manual, 1976, volume 2 (engine) or the Motorcraft Carburetor Service Manual, volume II, dated 1977. It covers the 4350 variations back to the original.

 

Ozzie H,

Yes, I have the shop manuals here and have looked over the overhaul job. The prospect scares me to death, so I hope I never need to cross that road! But, where would I get the correct overhaul kit if need be??

 

summit, jegs or ebay

 

As PBY said, they are readily available. Shop around for the best deal. If it is working well again, perhaps you don't need to do anything. The crud will likely remain on the bottom of the bowl and not cause difficulties. ????? But you don't have to be afraid of the job. I'm far from an "expert", and I was able to accomplish the deed. The "secret", if you will, is to understand the principles of operation of the carburetor, and be able to read and understand the shop manual or overhaul manual, and have enough time to devote. Hurrying is dangerous. You can make photographs at each stage of disassembly. Commercially rebuilt 4350s are also available, but the expense is far higher, and I found that I prefer my own work to the so called "professionals". The 4350 isn't liked by some Ford owners due to its nature to become problematic more easily, but I've found that when everything is set properly it can be just as reliable as a GM Quadrajet or any other carburetor. Mine is doing well. Best wishes.