So I just my first boat, a 1986 Alumacraft Side Console with a 40 hp motor. Boat wasn't running when I first got it so did a basic tune up to get it going. First time on the water it started up fine but would only go about 3mph, if I gave it anymore throttle it would make a grinding noise. It would sound like it was ready to move but not go anywhere. I'm not sure if this is a problem in the lower unit or not but wanted to see if anyone on here had any ideas before taking it somewhere. I know the motor is going up to 30 years old so it could be coming to the end. Any advise is appreciated. Thank you.