I tried using my 47 1-1/2 ton this weekend to haul dirt, and it kept stalling on me after about a mile down the road. I towed it home, replaced the fuel filter, and then it did the same thing to me the next day.

It was 90+ F both days, so pretty warm. Several people immediately said vapor lock. We used to use this truck all the time on hot days hauling grain during harvest, with no issues, so why now? I didn't even make it to the quarry to get a load of dirt, so it was still empty.

 

you could try driving around with the fuel cap off and see what happens. another thing it could be is maybe fuel pump going bad. sounds almost as if you are using up the gas if the fuel bowl to go a distance and the pump isn't keeping up or possibly the carb needs rebuilding.

 

I rebuilt the carb this spring, and it had been working good until now. I put on a new fuel pump this afternoon, and its running good...so we will see what happens on a hot day.

 

This new Gas we have had bestowed on us with the Ethonol, doesen't help matters much as I heard that it is very corrosive.

Second as for Vapour Lockwell that s caused by a number of factors, such as a possible pin hole leak on the draw side. If you have an AC Pump on your Truck its not a ford original, and the fittings are different thaan those of the ford originals. If by chance you have had the Fuel Pump rebuilt the small diaphrams in the top could be the off shore ones and they are garbage, yes they work for some time then they start giving trouble.

Keep in mind Gas is cold and under the hood is very warm therefore causing condensation, which in turn the vapor lock as it is known. Check all your fittings, make sure there are no corroded lines check the fuel pump bowl for bubbles or not near full ths is an indication. Also you could have a small piece of dirt under the needle seat in carb, make sure all the screws on the carb are snug, etc etc.

This can be a royal pain in the butt but definitly there is an issue causing this, and it very well could be the Ethonol at work. I use at each fill up a small baby food jar with motor oil to each fill up it prevents rust in the tank and will help prederve your fuel system. These old Cars/Trucks are starting to become 2 cycle engines now, the same applies to the Diesel Engines guys are using cocktail mixtures on them as well.

Sorry for the ramblin on hope you locate the issue and post it back on the forum for others that are experiencing the same.