Time with light at full throttle to 22 degrees before top dead center. If dist is in good condition, then the timing will retard to close to top dead center at low idle speed. If you try timing to top dead center at idle without making sure full advance is 22 at full throttle you will be no better off than you are now.
Carburetor is not the same as an M as it has different idle circuit. If it still smokes at low idle and not at higher speeds, most likely the idle jet inside (the long, skinny, jet with the tiny hole) is damaged or even missing.