Re: Atomic 4 Throttle
Exhaust could be partially blocked. Flaking metal in a raw water cooled engine can cause a temporary blockage. A collapsing exhaust hose. etc...
Fuel issues, air or spark issues. My old A4 ran once on fuel so bad it looked like chunky soup when I pulled the carb apart, would not rev very high but kept plugging along.
One of the great things about those engines is that they will keep running, just run like crap.
There are many possible answers. You need to duplicate the problem so you can trouble shoot.
'88 C&C 30 MKII