29 PU dies at stops

C

Chris Chicago

New member
My truck starts and drives fine but, when I come to a stop it dies. If I pull down on the throttle to increase the speed it doesn't die.
I'm sure it's a simple setting. Not being a mechanic I don't know what it is.
Suggestions please.

Chris
 
Have an original Zenith carburetor? They are a bit sensitive to float level. That is a common symptom. The fuel sloshes forward in the bowl and the engine dies. Start there.

It is also possible you have a collapsed spring behind the camshaft thrust plug. Easy front of the engine wrench fix.
 
Engine dies when vehicle comes to a stop

Common Causes

Float is set too high or a pin hole absorbs gasoline into float.
Compensator Jet Orifice contains dirt or rust, or is too small.
Idling Jet Orifice contains dirt or rust, or is too small.
Idle Air Adjust Screw is mis-adjusted or too short, collapsing spring before it seats.
Throttle Idle Adjustment Screw is mis-adjusted.
Upper Casting Idle Jet Passage is restricted to Idle throat port.


courtesy of:

http://www.model-a.org/symptoms.html

If there is any slop in throttle shaft/plate fit, it will stall.

Life is too short to put up with stalling carbs. :rolleyes:
 
Had same problem.Turned out the timing was to far advanced . Retarted the timing solved the problem .
 
Chris Chicago said:
My truck starts and drives fine but, when I come to a stop it dies. If I pull down on the throttle to increase the speed it doesn't die.
I'm sure it's a simple setting. Not being a mechanic I don't know what it is.
Suggestions please.

Chris
Click to expand...
Chris,
If it is idling well, except on hard stops, all I can say is, "Welcome to the world of the SLOSHING Zenith carbs!":D Common problem. Some will say they corrected it by altering float levels???? Fuel sloshing on hard stops just floods and/or leans it out when stopping HARD. When in traffic, I just leave my hand throttle down a couple of knotches in case of sudden stops. Bill W.
 
I do the same as Bill when coming to a hard stop to help negate the problem. Mine used to do it at all stops, but then I took the carb apart, cleaned everything out. Soaked it in carb cleaner and replaced the check valve. The old one was a bit sticky and wore. After that, no issues making normal stops and only a rough idle on hard stops. I still normally hit the throttle a bit just to be safe.
 
one more thing to add to the list of potential causes: a vacuum leak somewhere:leaky fittings , manifold gaskets or windshield wiper motor. Its not uncommon for the throttle shaft to be worn at the bearing points. A new shaft and/or bushings installed in the worn carburetor body has corrected it in several cases I have dealt with.
 
pat in Santa Cruz said:
Its not uncommon for the throttle shaft to be worn at the bearing points. A new shaft and/or bushings installed in the worn carburetor body has corrected it in several cases I have dealt with.
Click to expand...

Same here. I am of the opinion that if you have to futz with your throttle lever at all when coming to a stop, you haven't addressed the cause.

While it might be a "common" issue with worn Zenith carbs, with perseverance, you don't have to put up with it. I don't with either of my vehicles.

Good luck!
 
Guess I would start with simple things first. Take the carb off, take the bottom bowl off, blow it out with air, and see if that solves the problem. I did this and my problem went away. Plus the idea of using the throttle lever in heavy traffic is a good idea just in case.
 
Before you start fooling around with the float level, etc, try adjusting the idle speed. There's a good website you can consult and it's called, Model-A.org
It's got good illustrations and should be helpful to you.
Rog
 
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