1977 75 hp HELP!!

i just got this 1977 75 hp chrysler outbourd, it looks like its been in a time capsule, so i thought it might be worth messing with, well, let me get to it. i changed the lower unit oil, i put a new empeller in it, i changed the diafram for the fuel pump. then i put gas in the tank and it fired right up. i took it to the lake and it would crank up and idle, but when you put it in gear, it died. i messed with it, and it would die every time. so i rebuild the carbs, but a water boot on it, and it cranked uo and went in to forward and reverse and reved up fine. it seemed like it was idleing a little high, so i started tweeking what i thought was the idle setting, im pretty sure it was the timing. becuase it started idleing down, then it died and i cant get it to crank back up, no matter how much i adjust that screw. were do i go from here? did i mess anything up by adjusting the timing while it was running? can i use a regular timing light to adjust this back right? can some one help please?

Post a pic of what you messed with,J