1953 Dodge M37 military fuel problem?

Yesterday I used my truck to run a small errand about 3 miles. I
thought that two thirds into the ride I might have heard some very
slight back fires but the truck is very loud anyway so it is really
hard to tell sometimes when you're driving. The performance didn't
seem to falter though. I got to where I was going, picked up the load
and started the truck up. It ran fine until I got it on the road. It
sputtered and surged and did this intermittently all the way home. I
made it into my driveway, blocking everything else, where it stalled
and with repeated cranking would not start up again. I didn't smell
gas so it didn't seem to be flooding. The carburetor air intake in
these trucks has a special "S" shaped elbow with a trap in it for
attaching a fording pipe. I've never done this but this arrangement
makes it impossible to prime the engine with gas. I tried shooting
starting fluid down the pipe a few times but each time there wasn't
even a "kick". I waited about 15 minutes and finally in desperation
shot a big load of starting fluid into the intake To my surprise it
started up and ran pretty well. I backed it into its spot and checked
it over. The gas gauge showed at least half a tank and the engine was
running pretty well with only an occasional slight miss. The only
thing I did find was that the engine was running a little rich. (A
slight adjustment of the mixture screw on the carburetor sped the
engine up I'm guessing a couple of hundred RPM's), after which there
was a definite improvement. It doesn't seem like a slight mixture mis
adjustment could have all of a sudden caused this problem because I
wasn't smelling any gas? I've dumped both alcohol and fuel system
cleaner down the tank as a precaution but I'm really at a loss for
what might be going on here. If anyone has any Ideas I would be very
grateful. Lenny

On Thu, 28 Jul 2011 06:27:30 -0700, klem kedidelhopper wrote:

> Yesterday I used my truck to run a small errand about 3 miles. I
> thought that two thirds into the ride I might have heard some very
> slight back fires but the truck is very loud anyway so it is really
> hard to tell sometimes when you're driving. The performance didn't
> seem to falter though. I got to where I was going, picked up the load
> and started the truck up. It ran fine until I got it on the road. It
> sputtered and surged and did this intermittently all the way home. I
> made it into my driveway, blocking everything else, where it stalled
> and with repeated cranking would not start up again. I didn't smell
> gas so it didn't seem to be flooding. The carburetor air intake in
> these trucks has a special "S" shaped elbow with a trap in it for
> attaching a fording pipe. I've never done this but this arrangement
> makes it impossible to prime the engine with gas. I tried shooting
> starting fluid down the pipe a few times but each time there wasn't
> even a "kick". I waited about 15 minutes and finally in desperation
> shot a big load of starting fluid into the intake To my surprise it
> started up and ran pretty well. I backed it into its spot and checked
> it over. The gas gauge showed at least half a tank and the engine was
> running pretty well with only an occasional slight miss. The only
> thing I did find was that the engine was running a little rich. (A
> slight adjustment of the mixture screw on the carburetor sped the
> engine up I'm guessing a couple of hundred RPM's), after which there
> was a definite improvement. It doesn't seem like a slight mixture mis
> adjustment could have all of a sudden caused this problem because I
> wasn't smelling any gas? I've dumped both alcohol and fuel system
> cleaner down the tank as a precaution but I'm really at a loss for
> what might be going on here. If anyone has any Ideas I would be very
> grateful. Lenny


When was the last time the tank was cleaned/replaced?

Could be some crud in the gas tank and fuel filter.
cuhulin

klem kedidelhopper wrote:

> Yesterday I used my truck to run a small errand about 3 miles. I
> thought that two thirds into the ride I might have heard some very
> slight back fires but the truck is very loud anyway so it is really
> hard to tell sometimes when you're driving. The performance didn't
> seem to falter though. I got to where I was going, picked up the load
> and started the truck up. It ran fine until I got it on the road. It
> sputtered and surged and did this intermittently all the way home. I
> made it into my driveway, blocking everything else, where it stalled
> and with repeated cranking would not start up again. I didn't smell
> gas so it didn't seem to be flooding. The carburetor air intake in
> these trucks has a special "S" shaped elbow with a trap in it for
> attaching a fording pipe. I've never done this but this arrangement
> makes it impossible to prime the engine with gas. I tried shooting
> starting fluid down the pipe a few times but each time there wasn't
> even a "kick". I waited about 15 minutes and finally in desperation
> shot a big load of starting fluid into the intake To my surprise it
> started up and ran pretty well. I backed it into its spot and checked
> it over. The gas gauge showed at least half a tank and the engine was
> running pretty well with only an occasional slight miss. The only
> thing I did find was that the engine was running a little rich. (A
> slight adjustment of the mixture screw on the carburetor sped the
> engine up I'm guessing a couple of hundred RPM's), after which there
> was a definite improvement. It doesn't seem like a slight mixture mis
> adjustment could have all of a sudden caused this problem because I
> wasn't smelling any gas? I've dumped both alcohol and fuel system
> cleaner down the tank as a precaution but I'm really at a loss for
> what might be going on here. If anyone has any Ideas I would be very
> grateful. Lenny

Vapor Lock? That's a standard scenario. Runs, gets herky-jerky, quits,
<wait a while>, runs again. Look for fuel lines near hot stuff.
Especially steel ones.

Or not...just my $.02


--
John Gilman

An old ''Trick'' for vapor lock is to wrap some wire around the fuel
line to help radiate heat off/away from the fuel line.Sort of a heat
sink, per se.
cuhulin

"J R" > wrote in message
...
> An old ''Trick'' for vapor lock is to wrap some wire around the fuel
> line to help radiate heat off/away from the fuel line.Sort of a heat
> sink, per se.
> cuhulin

We used aluminum foil, and it CAN help in some cases.

Perhaps it was aluminum foil I was thinking of.Borrow a roll of it from
the kitchen and have at it.
cuhulin

On Thu, 28 Jul 2011 12:29:53 -0500, J R wrote:

> Could be some crud in the gas tank and fuel filter.
> cuhulin


JR...?

Had to hop on Windows Live ID for WebTV.That's why the J R.

Who shot J R?
cuhulin

J R wrote:
>
> Perhaps it was aluminum foil I was thinking of.Borrow a roll of it from
> the kitchen and have at it.

How is that going to help if the problem is the fuel line is absorbing
too much heat from nearby hot components?

If you insulate the fuel line in the neighborhood of hot components the
fuel will stay cool. The fuel in the fuel tank should be cool enough and
the fuel in the line will stay cool as long as the parts of the metal
fuel line that are near things like exhaust manifold, radiator hoses or
engine block. Even the hot air flow from the radiator on a hot day can
add a lot of heat to a metal fuel line. Modern fuels have lower vapor
pressure than years ago so vapor lock is more of a problem with
carburetors than it used to be.

-jim