merc 40 4 stroke electrical

[LCLE]

Drunk cousin hooks battery cables up backwards on my merc 40 4 stroke what have I fried? 1A40311BZ SER# 1C20541. Fuses blow instantly when I attempt to start it, but do not blow until I turn the key. Jumping the start solenoid will crank engine, but it does not start.

 

[Texasmark]

The rectifier diode(s) in the rectifier/regulator module is/are connected anode to ground and there is nothing else in the circuit. Reversing the battery connections puts forward bias on the diode(s) and the high current burns up the junction which fails in the shorted mode. Other than that he probably didn't hurt anything unless he bent the pointer on the fuel gauge but not that likely if you have one in your boat. Go to the top of this page and look under parts and accessories.