1991 Mercury 150 Black Max XR4- Charging system

Joined
Aug 11, 2013
Messages
7
Hello,:facepalm:
I recently purchased a bass boat powered by a Mercury 150 Black Max XR-4. I noticed the cranking battery is not charging. A certified marine mechanic suggested I check the alternator???? I am not locating this anywhere on the engine or any lead wires ran back to the battery for that matter.. Tested the battery while idling to be convinced there is no voltage being sent to the battery. Can anybaody clear this up for me, Does this motor have a alternator/ generator? I feel like im chasing geese. Thank you so much.
 

Barnacle_Bill

Admiral
Joined
Feb 8, 2004
Messages
6,469
Re: 1991 Mercury 150 Black Max XR4- Charging system

Your "alternator" is part of the stator. It is a very simple system and the rectifier/regulator is the most common part to go. I highly recommend you get a manual and it will give you instructions for testing it.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,036
Re: 1991 Mercury 150 Black Max XR4- Charging system

That motor looks to have a stator and rectified. Find the two yellow wires tha come from under the flywheel and trace them to the square black rectifier. Likely the rectifier is bad. Test and replace it.
 
Joined
Aug 11, 2013
Messages
7
Re: 1991 Mercury 150 Black Max XR4- Charging system

Guys, Thank you so much!! It turns out......bad rectifier..:rolleyes:
 
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