Good afternoon y'all, I just received an old '78 model Marquis i/o Mercruiser 120 from my in-laws as a gift, and have some hopefully simple questions. I'm new to boating and don't know much, so with that, on the dash, there's a gold looking screw type water-proof cap, which holds what looks like a fuse? There's not a fuse there, so I don't know what it does or is for? Any ideas?<br />Also, I've figured out that the trim works but the trim gauge doesn't work, as the wires on the stern are corroded and mostly missing. They look fine inside the boat, up to the motor/ stern. My question is, can I just solder up some new wire from the wires sticking out of the back of the boat to the trim (gimble?). I'm not sure what it's called, but it's the small round discs on each side of the stern? Are these the trim motors? Please excuse my ignorance of proper terms. 
) If I can wire new lengths of wire here, what gauge, type, etc? I would assume they would need to be some sort of marine grade, water-proof wire?<br />Thanks for the help, newbie T
) If I can wire new lengths of wire here, what gauge, type, etc? I would assume they would need to be some sort of marine grade, water-proof wire?<br />Thanks for the help, newbie T