The Stovebolt Site Forums The Shop Area Engine Shop Carter Carb Problems

Hi Guys, I have a 1942 chevrolet fire engine, 235.. It was running well, last carb rebuilt was appx 9 years ago. I live in Buffalo, so it stays off the roads in the winter time,but i still keep fresh fuel in it, use stabilizer around october/ november and have never had an issue. This past friday i took it to a car show, around 30 miles one way. It has been running fine, got to the car show and at idle it could barely keep running without my foot on the gas. at idle it will eventully die. If i hold my foot on the gas there is a real heavy miss, but pulling the choke out a bit makes it run much smoother and will prevent the problem. On my way home from the show, it would run excelled in 4th gear at 40mph no issues, but when i go to stop at a signal, put the clutch in and shift to neutral it conks instantly. Do i have plugged jets? where do i start on this carb?

It sounds like you've got some idle passages clogged. Try this - - -open the idle mixture screw up a couple of turns, then rev the engine up with the air filter removed, and clap a hand over the air horn. The manifold vacuum pulls a high volume of liquid gasoline through all the passages in the carb, and it will flush out small pieces of debris, or possibly dissolve minor gum deposits. Before the engine stalls, let it have some air and clear out the flood. As soon as it revs up and runs smooth again, repeat the strangle maneuver. If three or four tries doesn't clear the problem, it's time for some teardown and a cleanup.
Jerry

which screw is the idle air screw? is it the only screw/spring on the engine? and opening would be turning it in, or out?

There will be two screws, one that sets the idle speed by bearing against the moveable throttle lever, and another one that screws into the carburetor base with a tension spring under it to keep its setting. This is the one you need to open up (counterclockwise). It controls the volume of gas vapor and air that enters the engine at idle by moving a tapered point into a hole in the carburetor housing. Opening up the passageway allows the gasoline to flush out any debris which is clogging the passageway, hopefully. If the procedure clears up the stall at idle, just turn the screw back to its original position and drive on. If not, it's time for a carb rebuild, and your rebuilder will readjust the idle speed and mixture as part of the reinstallation process.
Jerry

Turning it to the left is opening it. My book says 1/2 to 1 1/2 turns out should be close. So turn it to the right till it bottoms out and then back it out to the left.