Hi Everyone.

I'm trying to preemptively head off summer vapor lock issues in my 47 ton and a half while I have time. (because with my luck they usually show up peak summer when all the tourists are in town and I'm running late on my way to farmers market with a load of vegetables) I'm pretty sure its a combination of a warm motor and boiling fuel/vapor lock because as soon as I pull over, open the hood, and put a cold wet rag on the fuel pump and fuel line for 5 minutes I can start back up and run another 5-10 minutes before the problem occurs again....

So a few questions
1)Is there a preferred modern water pump to replace the original ones that will allow me to run cooler or should I just have both of them rebuilt?
2)Should I add in a spacer on the fuel pump or carb? I had a guy in a 46 pull in beside me during my first vapor lock episode and suggest something of the sort but I was overwhelmed enough at the moment that I didn't totally process his advice.
3)What is the best way to reroute or shield the fuel line to help keep it cooler before it gets to the engine compartment?

I appreciate any advice as this truck is almost twice my age and I feel like I have a lot to learn.

 

Your fuel pump (If its original) operates from a push rod and a lobe on the camshaft. Putting a spacer under the pump would do more harm than good (unless you replace the push rod with a longer one). It was a common problem back in the day. The cam/push rod would wear and you would loose some length which resulted in a loss of stroke on the pump which translated to a fuel delivery problem. There are several fixes. A longer push rod or an electric in line fuel pump are both options. (Be careful if you chooses an electric pump. Those old engines didn't require much fuel pressure at all. You might end up with gas leaking out of your carb.) A quick road side fix would be to jam a small piece of leather into the fuel pump where the rod goes. The leather soaks with oil and doesn't wear the rod but gives a little longer stroke. It doesn't take much at all. I used a common paper punch and punched a hole in the belt that I was wearing. I dug the little piece of leather out of the paper punch and jammed it into the fuel pump. It fit like a glove and did the trick.

 

Had some vapor lock problems in my '39 p/u. Installed an inline electric fuel pump with a toggle switch and and solved the problem. Also installed a fuel pressure regulator set at 2.5 psi. As far as water pumps go I'd send them to Skip Haney in Florida. He is the go to guy for water pumps, IMHO.

 

Ditto on the fuel pump, got one for my panel from Napa to run when it got too hot. Never had a problem with my 1.5 ton, flushed the original radiator and block, ran it for a couple of years with N.O.S pumps in parades and traffic, no issues. Got a N.O.S. radiator and now it runs even cooler so I have not tried the pump on that one yet, make sure the line is well away from the head and manifold, watch the glass bowel if you have one to see if you are getting boiling there. Post some more photos of your truck when you can.

 

Thanks guys. I'll focus on making sure the cooling system is 100% and consider the electric fuel pump idea.

Here's a couple pictures of the truck.





We still put her to work for light loads



Her main job though is attracting (distracting) customers at market.

 

I'd definitely buy veggies from someone with a great truck like yours. Airtex E8902 is a popular choice for a 6-volt fuel pump since it is low pressure and does not require a regulator. Momentary contact switch under the dash. Install the pump as close to the tank as possible. Amazon and RockAuto had the best prices the last time I looked. The spacer the guy mentioned is a phenolic spacer that goes under the carb. It keep the carb cooler to reduce fuel boiling. Robert Shewman at Gadgiteer@aol.com sells a spacer with longer studs and gaskets for $30. BTW, Skip Haney's email is skip@fordsrus.com. He also does coil upgrades to modern coils in the original cases to better deal with heat. No thermostats for summer driving and distilled water with lube and anti-rust gives the best cooling. But in Montana you'd have to put the stats and anti-freeze back in for winter. Good luck.

 

A very beautiful truck. Some farmer was VERY careful about his fenders for many years and you are the lucky heir to his diligence. The photos are exceptional as well.

 

nice truck and good looking bed!

 

1 - I prefer the new production ball bearing water pumps with the ceramic seals. These pumps don't run cooler than the original since the stock pumps will flow a lot of water. The benefit of the new pumps is the newer seal. If you do decide to rebuild I too have heard good things about Skip, but I haven't personally done business with him.

2 - I have not needed a spacer while driving flathead V8s in Texas.

3 - Find out if you really had vapor lock or if you have a coil that fails when it gets hot. Carry a can of starting fluid. When your truck gets cranky spray starting fluid on the coil, it will cool the coil off. If the truck starts up imediatly you need to fix your coil. If that doesn't work spray the starting fluid into your carburetor, if you have fuel delivery problems the engine will run on the starting fluid for a few seconds.

Nice truck, thank you for sharing the pictures.

 

Thanks for all the advice. I really appreciate it.

Yes, an old farmer was very careful with this truck. We call her Wild Rose in honor of her northern prairie heritage. The only reason they sold was they were trying to drum up cash for farm expenses after taking a monster hailstorm the previous season. The thing that blew me away was that he said he had two more in a barn down at his son's place that were in "better condition" The bed was in rough shape when we got her so we rebuilt it with tongue and groove pine from a local custom mill.

I hadn't thought to pull the thermostats but that's a quick and easy improvement if it helps. I'll pull them for July and August and see what happens.

I'll also pay attention to the coil. I did have the coil bracket crack last august. It would bump and short against the oil filter housing on rough roads. That was the nastiest, most intermittent misfire until I figured that out. Felt really dumb once I did too.

 

It is just one long learning experience. Never feel dumb. Just celebrate that you figured it out. Remember, always start with the simplest possible cause/fix and move on from there. BTW, last summer on an 80-degree day I pumped with my avatar for two hours, shut down for awhile (muster organizer's request), and restarted with no issues to pump another two hours. I'd guess I run the engine at around 1,500 RPM while pumping. I run thermostats and antifreeze because I had the fire engine in unheated storage. Will continue to do so even though I have a heated garage now; lost power in March for 5 days due to a windstorm. Good luck.