HELLO, I have a 1972 mercury 1150 outboard on a 72 glastron gt 160, my problem is it will start up and die. I have to hold the throttle lever 1-1/4 of the way up to keep it running, and is slow on picking up rpm's . I can have 2000 on the tach, and push the throttle all the way foward and will rev slow to about 4900-5100 rpm and that's it. if it helps this motor has only been in fresh water and has aprox' 75 hours on it. It was used very little but, has been run every year. if someone can help that would great, thanks.