Main engine fuse blown while sitting ?

[yzf125]

Hey guys, My boat has been stored in the garage for the winter, it has a 2002 Mercury 75hp ELPTO. I have done nothing but charge the batteries every month, I went to raise the motor the other day and nothing worked so I checked the fuse on the motor and noticed the Main engine fuse "20 amp" had blown ??

What could have caused this to happen ??

 

[Jugbait]

I had the same issue one time. The remedy that I found was to take the connections loose from the batteries and clean them with a wire brush as well as the battery terminals. This solved the issue.

 

[yzf125]

My terminals and battery are all brand new, no corrosion on them and the battery charged on a 2 amp trickle charge setting.