I have a 1973 85 hp johnson, was my grandfathers so sentimental to me. i had it reworked last year, and it's been fine so far this season. Somehow now the battery is being ran down everytime it is not on the charger, i took it off the charger overnight and it wouldn't turn the motor over this morning. i had the battery tested and it was fine. the only thing running off this batter is the engine itself everything else in the boat is running off a seperate battery. Any ideas on what the problem may be?