First thing to do is to figure out why the choke doesn't engage.
The factory choke was spring loaded. After you shut off the engine, the spring would cool down and put pressure on the linkages. You had to kick the throttle to the floor once quickly to get the choke to engage. When the choke spring warms up, it pulls tension off and pulls back on the linkages to disengage the choke. If you just let it idle with the choke engaged until it is warmed up, it will stay engaged until you kick the throttle. When you do, you'll notice a big drop in RPMs.
With a mechanical choke, you may have to hold the throttle open while you work the cable. The throttle is spring loaded and applying pressure to the choke linkages. In order to get it to work right, you may need to hold the throttle open and then monkey with the cable to see if it does anything. Give that a shot and see if that gets the choke working. If not, you have to dig into it to figure out what isn't engaging. The linkages may be jammed or gummed up and dirty.
Assuming you get that working, get the engine up to operating temp and make sure the choke is fully disengaged and the fast idle cam is not holding the throttle open. On the choke side, there will be a screw on the throttle arm pushing up against the fast idle cam when the choke is closed. When open, the cam should move out of the way and let the throttle close all the way.
Once you get the choke adjusted properly, you may still be running too fast. If so, you'll want to look at the idle adjustment screw on the other side of the carb from the choke. It's a screw on the throttle linkage towards the front of the engine. Turning it in will cause the engine to speed up, turning it out will cause the engine to slow down.
Give all that a shot and let us know what you find.
