I have an 85 mariner 40hp made by yamaha. The motor runs good but is not charging the battery. Volt meter shows spuratic DC voltage some in negative numbers. Motor will run without cables attached to battery (Will crank with pull rope and run). Have been reading about rectifier but not sure what one looks like or where it is on motor? Can someone help with what to check? I have a donor motor and changing parts is not a problem.
