On the positive battery cable, motor is 40 hp Mercury, looks more like my Yamaha than most Mercuries I have ever seen but it is a Mercury. Anyway what is the box for (half size of a match box) and a little bolt and nut sticking out ofit. It sat up a year and we were trying to restart...yeah we did all that and I couldn't get full spark until I whacked the box a few times with screwdriver. Works fine now , but what is it?