I have a 1984 7.5 Mercury.On the handle it sayschange or shift then start then to fast. When I turn the throttle handle it turns to just past start and then stops. It seems this is as far as it will go. It isn't able to turn to the fast position. Can anyone tell me whats the problem.Thanks<br /><br />P.S. Is the full to oil mixture at 50 to 1