• Notice for iPhone users: DO NOT use the image size reduction option when uploading photos to the forum. This causes portrait images to post as landscape. We have added a warning to the image insert pop-up as well.

Carter, BB2 needle valve idle adjusters

Wayne

Wayne

Legacy Registered User
City
Cape Coral
State
FL
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
 

Attachments

  • IMG_1774.jpeg
    IMG_1774.jpeg
    225.7 KB · Views: 2
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.
 
spankrjs said:
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.
Click to expand...
 
Thank you for the clarification Sir:
Any idea what might be going on with the fuel flow and the spluttering?
I have taken the carb completely off, cleaned it, new gaskets. I'm 100% sure that it was put back correctly - it's very frustrating.
 
Wayne said:
Thank you for the clarification Sir:
Any idea what might be going on with the fuel flow and the spluttering?
I have taken the carb completely off, cleaned it, new gaskets. I'm 100% sure that it was put back correctly - it's very frustrating.
Click to expand...
Did you perform the steps for reassembly and adjustments similar to the FSM?
Not 100% sure of your exact issue but the main metering jets may need some adjustments :shrug:
 

Attachments

Wayne said:
Can I ask you were you got that?
I will read that later.
Thank You very much.
Click to expand...
Well, I had tried to send you a really informative site "Jeep Adventures Under the Hood" that I had bookmarked. All the links no longer work:cry:


Anyway the link I have for the FSM still worked so I downloaded the section of the carb to send to you, the full FSM is here:


The linked site also has lots of other good info.
 
You must log in or register to reply here.
Back
Top