1983 Mercury 150 Ser # 6431959. After a day of fishing we get ready to go back to the ramp to go home. Crank up and idle about 70 yards out of a cove then attempted to get on plane. No dice front of the boat stood up and the motor sounded like it was hitting a rev limiter. Now yes I did notice all day that it was idling rougher than usual, after it had been sitting for about 3-4 weeks. Any way did a compression test today, (1) 105, (2) 118, (3) 115, (4) 118, (5) 115, (6) 119 [was touching not covering the 120 mark so]. So what do yall think? Yes I could rebuild it but it's still a 35 year old motor with new parts. Or bite the bullet and get some thing new or at least newer? I did notice this chunk out of the head gasket when I started putting stuff up so not sure if it's all the way through. Guess I will at least take that head off to see.