Expert: Brad Sears - 9/30/2008

Question
Sir:
I have a 74 Dodge Pickup with a 318 2V, auto trans, 126,000 miles.  I continue to have a hesitation (worse when cold, nearly goes away when warmed up well) when first starting to press down on the accelerator pedal.  I'm guessing the hesitation is due to a lean fuel condition as the throttle starts to open.  Feathering the pedal (gentle, quick 1/2 inch pump x 3 or 4 to the pedal) will bring it through the hesitation, otherwise it may die.  I'm not sure as to how to adjust the two idle jet screws on the carb.  I'm guessing turning counterclockwise will richen the idle mixture.  If correct, do you think this might help with this hesitation?  
If you don't think this will help, do you have other suggestions?  There is a 2-3 year old rebuilt carb on the truck.  This hesitation has been with this truck, ever since I've owned it in 1980.  It just seems to be worse now.

Thank you for any help you might give me.

Answer
Your vintage truck is part of the reason that the industry went headlong feet first into the fuel injection poor in the early 80's. We had so much trouble getting engines to run right as they were leaned out soooooo much trying to get the emissions down. Now your engine was among the early vehicles equipped with EGR valves. And unless all the emissions devices are in perfect order this type of hesitation is the norm. As far as the carburetor adjustment goes, yes counter clockwise richens the mixture. The simple procedure is to turn the mixture screw counter clockwise until you loose engine speed (RPM's). The turn the screw slowly clockwise to the highest RPM and then a bit more to just loose a little RPM. Turn the screw back about an eighth to a quarter of a turn and repeat with the other screw. This is the way that I have been setting them. It is not the factory recommended adjustment but it works for me.
Brad