Carb question

[underliner6]

On my new to me K20. The truck starts cold and will idle to operating temp just fine. As soon as throttle is applied and the choke is disengaged, the truck will spudder and stall unless the rpm’s are maintained with throttle. Of course this means it stalls while coasting down the road or when I stop at a red light.

I have read up that it could be a variety of things. I’m inexperienced with carbs and don’t want to screw it up as it has been running good up until now.

Where should I start? Will adjusting the idle screws a slight amount to increase RPM help? Since this happens after the truck is warmed up, do you think that the choke is not the issue or should I try adjusting it? Thanks for any info to help a newb try to figure out this Edelbrock 4 barrel.

Jim

[geezer#99]

Ah!
Edelbrock!
First thing to do is increase the idle speed and then look inside the carb for any excess fuel.
Sounds like it’s flooding.
Here’s a pic to show you where the idle speed screw is.

http://jimsprojectgarage.weebly.com/tuning.html

[rockyrivermark]

What type of fuel pump to you have? Eddy’s don’t like much anything over 5 psi.
Eddy instructions say up to 6.5 but this has come up here many times before and solution often was getting psi down
Just something to check.
Did you verify that the butterfly is fully open when warmed up? I’m assuming you did that but if not that’s the first thing to do
I read on this site that 99% of carb issues are ignition.
Check timing etc also.
Points or hei?

[underliner6]

Thanks for the responses guys!

I’m not sure what kind of fuel pump I’m running. I will check.

I will start with the adjustment of that idle screw and see if I can get her in range.

Thanks for pointing me in the right direction for a starting point.

[Steeveedee]

Also check around for vacuum leaks. Spray around the throttle shafts at the base of the carburetor with WD-40 or carburetor cleaner. Any change in idle speed (up or down) indicates a vacuum leak. It's very common for the choke to cover up a vacuum leak, and once the choke is open the leak becomes apparent with the symptoms you are experiencing.

[underliner6]

I adjusted the idle screws and got the truck where I wanted it! I also took the advice and checked for vacuum leaks which I did not find any.

Thanks for everyone’s advice. It was a trivial fix but hopefully this thread can help someone else in the future.

[Steeveedee]

Excellent! It's always nice when things work right.