1985 Mercury Outboard V-300 V-3.4L Shop Service Manual, Page 35Get this manual
BATTERY CHARGING SYSTEM DESCRIPTION
The ball ery charging system components are the stator, recti
fi er and battery(Figure 2) Alt ernating current (genera ted in sta tor alternator coils) nows to the rectifier which changes the
alternating curren to direct curren for charging th ballcryThe rectifier may he damaged by: I) reversed batt ery lead s2) runni ng the engine with ballery leads di sconnected and 3) an open circu it, such as broken wire or loose con rrCClio n
Visuall check the following: 1Check for co rrect batlery polari yRed cable I0 posi vc (+) batt er terminalIf polarity was in correct, check fo da rn aged reclifi er2Check for loose or corroded battery term inals3Check the cond ition of the battery4Visually inspect wiring het ween stator and ha tt ery for cut s, chafing and di sconnected, loose or co rroded con nectionsSEx cessive electrica load (from too man accessories) will cau se batt ery to rUII down If visual inspection determines that batt ery and wiring is OKperform the following sial or and rectifi er test: