Flathead won't idle

It is here, I just bought it from a guy in Kansas, it takes awhile to get it to run. Lots of pumping the gas and it eventually starts. Hard to keep it running unless you hit the throttle. As soon as you let off the throttle, it dies. If you rev it it sounds great, but as soon as you let off the throttle, it dies. Starts right back up but you have to keep her running with the gas pedal.

The truck in question is my new avatar photo.
 
Start by inspecting the tank condition, the fuel line, and carb. They all will need to be cleaned or replaced. Make certain the fuel pump is working and any soft lines are sound. You'll also want to check for vacuum leaks. Good luck and enjoy the journey.
 
The Power valve is only triggered when your foots hard on the gas .If it runs ok above idol then there is no shortage of fuel . above the idol l RPM .If you have no choke hooked up then it will be hard to start ,You need to first do what Walt said blast out the idol circuit. !!If the choke was hooked up then you could assist the slow running starvation problem ..
 
I worked wonders in the behaviour of my carbs by lapping the mating surfaces flat, using wet and dry paper on the flat table of my drilling machine. Other things causing problems might be a ruptured float or a sticking or badly seated needle valve. There could be big air leaks elsewhere too causing problems.

It shouldn't be too hard to sort it out, but will require some tinkering.

Will it idle at a fast idle if you open up the idle screw?

Mart.
 
Go for the most probable first. Dirt / rust in the carb idle circuit, gas lines and gas tank. Many vintage vehicles which haven't been run regularly and stored without proper steps to prevent rust and shellacked ( gas stabilizer with rust preventer in tank and carb ) gas cause problems like this and worse. I would remove the carb and clean the idle circuits, blow out the gas line, drain and bore scope the gas tank to get a look at conditions. Do what's requirede after observation. Even if you blow out the idle needle screws the problem can reoccur if dirt, rust, debris is still in the gas line / tank.

Looks like a nice truck, good luck and have fun!!
 
I am going to pull everything fuel related, gas tank, carb, etc. I'll let you guys know what I find out.
 
Will not hurt anything, but sounds a little drastic for an idle problem. Think I would start with the carb and make sure you have a good filter in the line. You would think a major issue other places in the fuel system would affect other than idle.

Note: Also, it may not be a fuel problem at all, vacuum leak?
 
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Vanspeed said:
I am going to pull everything fuel related, gas tank, carb, etc. I'll let you guys know what I find out.
Click to expand...

Just realize that if you don't take it one step at a time, it's possible that you'll never know for sure what the true culprit was. DD
 
I had this happen to my stock `46, thought maybe the idle passages were clogged, i just got the car up to top speed and let go of throttle real fast a few times. snapping the throttle plates shut and let the huge vacuum in the engine do it`s magic. runs smooth now. :)
 
I just spent chasing a similar problem on a 1950 non Ford that had sat for several years.
Lots of Ethanol caused brown powder, rust, and varnish to clean in the lines, fuel pump, and carb.
Last issue to be corrected was an air leak on inlet side of the fuel pump (sucking air) that did cause a fuel leak.
Would run at fast idle for short while and then die. Sometimes it would restart and other times had to bottle prime it.
Runs great now but it took multiple clean outs and carb kit.
 
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