The Stovebolt Site Forums The Shop Area Engine Shop Zenith carb question

I have a Zenith carb on a 57 270. Number on carb is 11475B. It has an adjustable main jet. I have attempted to turn this but couldn't. I didn't try to force it.
I am having fuel in the oil issues, and have changed the fuel pump twice with no change. The truck runs well, but I suspect the carburetor may be the issue.
Looking down the throat while running, I see no excessive fuel, actually don't see any.
Can someone shed some light on this adjustable main set up, with proper adjustment techniques for this carb. I have not done anything to it, and haven't located a rebuild kit if that is what it needs.
I hesitate to attempt a rebuild on my own with all the small parts, springs, balls etc. and no experience in this.
Any help is appreciated.
Thanks, Jeff

Jeff,

Post a photo of the adjustable jet and the carb body. That will assure that people are providing advice about the correct carb/part.

If you want the name of a good re-builder: Larry Isgro

No way to post photos at this time.
The adjustable main looks like this.
I appreciate the link for the rebuilder.

It requires two open end wrenches.

Use one wrench to hold the largest hex surface (this is what holds the assembly in the carburetor). Use a smaller wrench to loosen the smaller hex surface (this is the adjuster "gland" nut, also known as a lock nut). Once the gland nut has been loosened maybe three quarters of a turn, the "T" handle adjuster should turn.

The gland nut tightens a fibre seal against the adjuster, both preventing the adjuster from turning, and also sealing against a fuel leak.

Once the adjuster has been turned to the required setting, retighten the gland nut.

An approximate beginning adjustment is to turn the adjuster in (clockwise) until LIGHTLY seated; then back the adjuster out(counter-clockwise) two and one half full turns.

Drive the vehicle at highway speed, with a friend following in another vehicle.

If your vehicle surges, the mixture is lean. Back the adjuster out further (counter-clockwise) 1/8 turn at a time. The adjuster is wide open at five full turns.

If your friend notices black smoke, the mixture is rich. To lean, adjust in the opposite direction.

TWO CAVIATS:

(1) ALWAYS use two wrenches to loosen/tighten the gland nut.
(2) NEVER use a wrench or pliers on the "T" adjuster. If it will not turn with your fingers, the gland is too tight. FAILURE TO OBSERVE THIS SENTENCE WILL COST YOU $$$$$$$

Jon.

Thanks for the instruction. I will be very careful.
I'll see where its set as soon as I get a chance.
I appreciate the response.

Jeff