were dealing with a 2000 90hp , 3 cylinder.<br />Carbs were rebuilt checked timing, and adjust it to 2 deg. btdc. Idle was adjusted rpm 900-950 in "N" and in gear droped to 750. The idle mixture was set to 1 1/4 -1 1/2 per. the book. Idle great for hour. with test prop on I ran the rpms up 3000-4000 in test tank. held for a couple minutes, to get the main jets working as well. droped back to idle ran great. taking the boat for a test ride runs great. runs great the next day. but three days later and the engine starts to cough at idle. only thing that I can see that was different between the days was the humidity. could the pressure change affect the carb's? if so do I ajust richer or leaner? or should i up the idle rpm?
