She's a buckin' Bronco

[strat1960s]

Here is my latest problem with the motor.


Let the car warm up for about 10 minutes before driving
At every intersection that I have to stop at the motor will be idling around 850 to 900 RPMs. Then there is a jolt in the motor. If I am stopped for more than a minute or two, it will jolt again. After the first couple of jolts the RPMs go back up to around 850 to 900. Now if I am waiting for a light to change, the jolts keep happening with less time in between jolts until the RPMs drop below 500 and then the motor dies.
This very rarely happens when it is warm outside. I am thinking it is a temp / choke related issue or a fuel issue
I have 9 stops from my house to the AFB. I average about 3 to 5 starts just to get to work.
If someone knows of a fix for this, please let me know.
Ted

 

[rbohm]

8) sounds like your idle mix is a bit lean for cold weather operation. try richening up the idle a bit.

 

[strat1960s]

RBohm,

I was actually thinking I should go up in jet size.
The tuning guide for the weber carb say that if the mixture screws are turned in more than 1/2 turn that I need to go up in jet size. The shop I took it to, to fine tune the carb tweeked the time and adjusted the valves a little to get it to idle under 1500 RPM. When I picked it up, I was pleased that the motor would idle at around 1000 to 1100 RPMs (still a little high). My gut instinct is telling me I need to go up in idle jet size. For those of you not familiar with the Weber 38 DGAS, there are 3 jets.
Idle jet, main jet and air corrector jet.
If anyone has any ideas where to start I would greatly appreciate it.
Thanks
Ted

 

[rbohm]

8) sure, you can go up one size on the idle jet, or turn the screw out a bit. try turning the idle screw out a bit before you change the idle jet. sometimes on webers that is all you need. and yes if you go 1/2-3/4 turn off where the initial adjustment is, then you need to go up or down one size on the idle jet depending on which way to turned the idle mixture screw.