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Charging system not working 90 Merc

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apbaseball

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90 HP Mercury 2-Stroke. Model 90 ELPTO.
It appears that something on the charging system isn’t working as my voltage does not increase on my voltmeter with the engine running.
Engine idles and runs great, tach works. What should I look for to remedy this issue?
 
Test AC voltage out of stator (2 yellow leads) to rectifier/regulator.
In order to read the AC volts you will need a DVA.

Volts DC from red lead(s) coming out of regulator/rectifier will also show the same as you get on battery terminals, fluctuating with rpm.

Also make sure the grounds are tight
 
trynhooker said:
Test AC voltage out of stator (2 yellow leads) to rectifier/regulator.
In order to read the AC volts you will need a DVA.

Volts DC from red lead(s) coming out of regulator/rectifier will also show the same as you get on battery terminals, fluctuating with rpm.

Also make sure the grounds are tight
Click to expand...
DVA for battery charging AC voltage? A regular DMM will suffice nicely on the AC 20V range. DVA is for the pulsed high voltage energy that supplies the power that runs the spark plugs. Since the DMM can't read short pulses over a long rest period, the DVA contains a rectifier, storage capacitor, and a bleeder resistor which accepts the narrow pulses which charge the capacitor to a nice DC voltage that the DMM can read.

The output of the regulator (larger of the red wires from the regulator module, goes to the input terminal of the starter solenoid......a convenient terminal block for B+ distribution. If you have the AC voltage at the output of the yellow wires and no increase at that terminal as the engine starts and continue to run then your rectifier/regulator module is bad......easily located, black potted aluminum framed, 11/2 inch square package on the Port side of the engine....red output wires go to that solenoid junction point.
 
apbaseball said:
90 HP Mercury 2-Stroke. Model 90 ELPTO.
It appears that something on the charging system isn’t working as my voltage does not increase on my voltmeter with the engine running.
Engine idles and runs great, tach works. What should I look for to remedy this issue?
Click to expand...
The tach output (grey wire) comes off the rectifier portion of the module. If you have no increase in the voltage at the larger red wire from that module with the engine running, the regulator portion is faulty.
 
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