You might have a different cam in the 1776 and the fix may be to increase the idle speed volune screw until it idles smoother. The other way things can go wrong is if you try to set the idle timing at 7.5 degrees BTDC with it idling too fast around 1000+ rpm when its warmed up with the choke still holding the throttle open ( blip throttle to reset it) which gives mechanical timing advance at idle which should not be present. . Then next time you start and it idles slower, the ignition timing is more retarded and it barely runs.