Re: Using a spray can of ether into a 4-barrel carb?
To answer your question SPECIFICALLY, spray it only into the primaries (usually the two front ones)
To avoid damaging your boat -- Don't spray it....
I think you already hit the nail on the head in your question above: to quote you above "...or just spray the two open barrels..." You shouldn't have any open barrels. At least not on a cold engine...
So, either your choke is stuck open (most likely) or your secondaries are stuck open (should cause very crappy idle, not very likely)
You will find that you will get much better responses if you provide engine and drive info with your question.....