Installing carb

I ordered a new aftermarket carburetor for my 9n Ford tractor. They sent three gaskets with the carb ,the gasket that connects carb to tractor. The carb will not adjust I only used one gasket. Should I install more.

Are all the gaskets the same size?

It should only need one.

Are you saying the idle mixture won't adjust? As in turning the screw in or out has no effect?

A carb can only work as well as the rest of the engine.

Is the engine properly tuned, plugs, wires, points, timing, cap and rotor, etc?

Is the compression good, valve lash adjusted properly?

Has the air cleaner been serviced? There is also a wire mesh above the oil cup that occasionally needs cleaning. Check the entire tube for mud dobbers and mouse nests.

How is the fuel? Fresh, clean, rust or trash in the tank? Anything in the tank will get in the carb. Even if new it only takes a tiny speck of rust to foul the carb.

Now, back to the carb...

Make adjustments with engine up to operating temperature, verify choke is fully open.

Things that will prevent idle adjustment:

Most common is idling too fast. The idle needs to be down around 400-500 RPM.

Vacuum leak. Any obvious vacuum leak, or in rare cases some manifolds can burn through internally between the intake and exhaust.

Clogged idle circuit, or wrong gasket between the top cover and the bowl. Idle fuel gets drawn up the hole beside the throttle bore. If the gasket is wrong, or the cover doesn't fit tightly it will not draw up idle fuel. The idle jet is very small, doesn't take much to clog it.

Not sure what carb you have, but most updrafts adjust backward from modern carbs. The idle screw regulates air, not fuel. Turning the screw in closes the air bleed and enriches the mix. Backing it out increases the air bleed and leans the mixture.

Hope this helps, let us know...

You only need one gasket. Any more will make it worse.
Is this a Marvel Schebler clone carb or a Zenith/Bendix type?

If M/S clone, Steve has covered pretty much every thing I thought
of. Let me echo his statement - idle air screw is in for rich <500 rpm.

Main adjustment should be set at about 1 1/2 turn off the stop
and the idle air adjustment at 1/4 to 1/2 turn. That should get it
running so you can let it warm up and adjust it properly after that.