Might be time for a new battery. Is it an older battery? It may be losing its ability to hold a charge. I know marine batteries aren't cheap, but at least it doesn't require pulling the motor apart :D

I am not too afraid of the virus. It seems to only be targeting the elderly, weak and young children like regular flus, so it's not going to be a repeat of the spanish flu which affected healthy adults as badly as the most susceptible of the population.