[Wiscbw]

A dealer recently installed a used 97 225 OX66 Yamaha engine on my boat. The motor runs great, however my electronics and gauges are not okay. Main problem is the motor is not charging the battery. The tachometer reads fine. Approx 40 volts AC out of the stator (only checked one line). One battery (new). I think the engine has 2 separate charging lines, one for each battery. I never see the voltage rise above the battery voltage with a volt meter. I charge the battery before use and stop when the battery reading on the speed gauge is around 12.2VDC . Does anyone have the Yamaha wiring schematic or suggestions for fixing this problem?

[rodbolt]

ya have to use the service manual. but a quick check is to use a voltmeter and test the voltage output of the rectifier/regulator. if its ok at the output there start looking at the battery cables and how the battery isolator wiring was run. some of the 3.1 motors used a 3 lead battery cable and the little lead was prone to break.other than that its inputs and outputs, garbage in ,garbage out.good in,garbage out, ya found the problem. that stator system uses a 3 phase altenator, check the resistance of each green to green and each green to ground.