The idle speed, when warm, is a bit low.
It's around 700 RPM and when slowing down from a higher speed, sometimes the idle speed drops very low and once in awhile the engine actually stalls on decel.
Also, at times, the RPMs hang when the throttle is released.
If the throttle is "blipped" the RPMs will drop to idle.
Someone put a fuel pressure gauge in line with the fuel feed line.
It reads about 3 PSI when the engine is running.
Removed the air cleaner from the carburetor to confirm that the choke is opening and closing properly (with the manual choke cable).
The idle speed adjustment is made with the screw (red arrow).
Raised the idle speed to just over 1,000 RPM.
It's a bit on the high side but the amount if fuel wasted with the slightly higher idle speed is negligible for the type and amount of driving that I do & it will make the car feel much smoother at idle than at 700 RPM (quite a lot of lumpy vibration/shaking at 700).
Also, it will ensure that the RPMs don't drop too much when decelerating from higher speeds and ensure that the engine will not stall.
The throttle return spring is on a lever with a couple of holes.
It was on the lowest hole (highest leverage but the shortest spring length/force when at idle).
Moved the spring up to the upper hole. This actually reduces the throttle return spring's leverage but increases the spring force at idle.
Tried it out. Seems a bit better but still doesn't seem quite right.
The best solution may be to find a stronger spring and put it back on the lower hole...
