Re: What moves butterflies? 1976 70hp Evinrude.
The butterflies are all connected via a common linkage on the starboard side of the carbs (left when looking at the motor), which in turn are operated by a cam that rides on a roller on the center carb's linkage. The cam is connected to a bellcrank, which in turn is indirectly connected to your throttle cable via a second, spring-loaded bellcrank. The spring-loaded bellcrank allows for variation in timing advance vs. throttle.
Anyway, if the carb butterflies aren't perfectly synched up, you will have running issues. Search on Link-And-Synch threads and you should come up with some good info.
