I've suffered with very poor cold weather performance (I.E. -20F) long enough.
It's so bad that at less then full operating temp it'll stumble when moderate throttle is applied.

I've a de-smoged carter YFA, sitting on a 300 with a 252 duration cam. I know the cam is the cause of the problom.

How do I properly adjust the mix on this carb. She starts great and idles well but am tired of the stumbling and stalling.

There are no vacum leaks. Ive got the idle mix tuned up to compansate but its pissing money out of my wallet.

Anyone know the proper sequence for tuning this sucker.

 

Hook a vacuum gauge to manifold vacuum while the motor is idling, and adjust the mixture screw until the needle pegs at its highest point and is steady. However, depending on what type of aftermarket cam you have, you may not be able to get it perfectly steady, so keep that in mind.

 

Where is the mixture screw?

 

I assumed you knew where it was because you said above you've already adjusted the mixture. Anyway...it's at the base of the carburetor. It usually has a spring under the screw head.

 

Thats the idle mixture screw. Im suffering poor off idle, and highway performance.

 

There's no "mixture" setting for anything other than idle. Verify that your choke is working, and if so the next thing to check would be the metering rod adjustment.

 

Got ahold of a carb shop. The only thing that can be adjusted is the meetering rod hight as you indicated. Though the guy said, "Its likely the accl pump". I can re jet it. jets are available but the matched meetering rods are not. I think I'll throw a rebuild kit on her and turn out the meetering rod a 1/4 turn.

Thanks for the help though.