carburetor operation

[cathken]

i operate a 1989 searay sundancer with a 454 mercruiser bravo one drive and the carb is a weber 4 barrel.i suspect the secondary of the carb is not opening properly.at what rpm should the secondary valves start to open and should the plates be fully open at 4200rpm?

 

[Quint4]

My secondaries kick in 3300 or so...

 

[cathken]

thanks for the response.can you hear or sense the engine powerchange when the secondaries kick in?