Robert:

Dar is correct in his method of adjustment, but he makes it sould a lot more complicated than it needs be.

Start the engine and go to full throttle, turn the needle in and out to get the fastest speed the engine will run, then unscrew the needle just a bit, until the speed drops a little bit.

Then close the throttle as far as you can and keep the engine running. Pinch the fuel line shut.

If the engine dies immediately it's too lean, Turn the mixture disc just a hair, moving the little notch toward the front of the engine and try again.

If the engine speed immediately rises when you pinch the hose, it's too rich. Turn the disc so the notch moves toward the back of the engine and try again.

The third possibility is the engine speed staying the same when you pinch the tube for a second or so, then the rpm will rise a little, and finally the engine will drop rpm. This is very close, from this point adjust the idle mixture asDar said, judging it by the way the engine answers the throttle.

All this supposes you have no problem other than the adjustments. But there are other problems you may have.

First, is your engine's carb a pumper or a suction version? Look at the first picture attached, if your carb has the extra screw like the one on the left it will not work satisfactorily without a pump. Wont even work with the Iron Bay or Cline pressure system, it requires a pump. Look at the second picture, the pumper is the top left, normally aspirated carb is top right. Might see the difference more clearly here.

Assuming you have the right carb the idle slit could be clogged with congealed oil, or its o-rings could have failed.

Take the carb off the engine, unscrew the needle and set it aside. Remove the circlip from the side, and the idle stop screw. Pull the throttle barrel out. Now pry the mixture disc out of the carb body.

Look at the third picture. The part shown is the K&B adaptation of the Perry, yoursw is not quite the same. You can see the hole on the side of the tubular extension, this is the idle slit that clogs. On your carb the slit is in the land between the two o-rings. Clean it with a small bit of typing paper wetted with acetone, don't use anything but paper - the size is critical and can be damaged. If there is any damage to the o-rings order a new set from Conley Precision or MECoA, they're not expensive.

Reassemble, adjust, and enjoy.

Bill.

PS: Before youo do anything to the carb check for air leaks, around the base of the carb, the engine's back plate, bubbles in the fuel line, and so forth. wr.