Expert: Everett Peacock - 3/7/2011

Question
Hi, I have a 1991 Mariner 90hp outboard, serial 09633677. On Sunday the motor would not idle whilst we were skiing. I found the aluminium cased black box bolted on top of the motor burnt out. It has 3 or 4 wires coming out of it. What could the possible causes be for this to happen. I dont want to replace it and it happens again due to a fault elsewhere. Many thanks, Louie

Answer
check the wiring a the engine for any melted wires...replace the rectifer.  It could have gone bad by itself..not a rare problem.. also check the stator output at cranking speed, should be above 20 volts AC on the low side and 150 and up on the high side..