High idle

[steplift20]

1988 150 mercury black max started her up on Saturday hard to start at first cause this is the only year I did not winterized her cause I had to bring her in to get the trim fixed so started her up and she's Erving high about 2000 rims let her warm up about ten minutes but she still revs high I'm thinking I should lower the idle by turning the screw but what else would cause her to rev high didn't rev high when I stop using her What do you guys think I should do first Thanks p.s. My wife is going to killmeif I have to take her to the shop again I need help cause I want to live Thanks