Carter, BB2 needle valve idle adjusters

[Wayne]

Hello :
Is anybody familiar with the two idle needle valves at the bottom of Carter BB2?

I have had an ongoing issue with the carburetor running sluggish at high speeds for quite a while.

I found out yesterday that one of these screws adjust the idle when the vehicle is standing still, and the other adjusts the idle at speeds?

If I run the engine and turn each screw in individually, both of them will stall out the engine, but I don’t know which one I turned to make the engine run smoothly at high speed.

When I get to about 40/45 miles an hour the engine starts coughing and spluttering, and I believe one of these needle valves can fix my issue I just do not know anything about them and I’m having a hard time finding anything about them on good old Google.

Thank you very much

 

[spankrjs]

Those are idle mixture adjustment screws, NOT idle RPM screws. Yes, adjusting them will change RPM because you are adjusting the mixture, so it will increase RPM and can stall the engine.

You usually leave those out IIRC 2.5 turns after gently bottoming them out. Then fine tune mixture from there.

The FSM goes through it pretty good in how to adjust them.

These adjustment screws will not fix your issue, most probably.