i have a 1976 evinrude 6 hsp outboard motor last time i had it out it stopped running after using about 1 gallon of gas,(which still had about two and a half gallons of fuel left,fresh fuel and outboard oil added to tank ,on the way to lake) i couldn't start it,i tilted the tank so the gas would be closest to the gas opening and it started right up,can anyone here tell me what the problem could be,i checked the opening part for the breather port on the gas tank, and that was fine,could this be a fuel pump problem or what?...thanks for your help