Hi ya Boot,
On a 4 corner carb start out with the engine off. Next turn each air fuel screw in until it bottoms out (SOFTLY), do not force when running in. Turn each crew out 1 to 1 1/2 turns. Start the engine. If it will not idle on its own, turn each screw out a 1/4 turn more. do this until it will idle on its own. Once the engine is up to temp. rev it up a few times between 3000-4000 rpm, see if it will come back to an idle with out a stumble. If not back out 1/8 turn again on all crews. Do the rev up test again until it doesnt stumble when returning to an idle.
Then adjust with the boat in the water. At an idle put boat in gear, see if it idles. If not out some more on the air fuel screws. Just an 1/8 at a time. If the rpm isnt high enough you must raise the idle screws in 1/16 to an 1/8 on each side, primary and secondary until you get your idle speed where you want it. If you need any more advice feel free to call the shop.