90hp v4 charging problem?

[nahuston]

Hello all,
I have done a lot of searching through old posts but I haven't found exactly what I need so thanks in advance for the help. 1991 johnson 90 v4... My fairly new battery died out on the water. I had charged it the day before so it should have been fully charged. I have a shop manual and it states that the resistance between the two stator charging (yellow) wires should be .62 ohms. I tested it and I get 0 (not open circuit). However if i check for a/c voltage out of the stator I get 52ish volts with the engine running. (not peak voltage, just using a normal cheap multimeter) I show 12.5 volts at the battery with the switch off or with the motor running but I have not let it run for a long time at high rpms to see if it goes up at all. Any idea if 50 a/c volts from the stator is normal and shouldn't I see at least a small voltage increase at the battery with the engine running at fast idle for 5 mins?
Thanks

 

[wilde1j]

Re: 90hp v4 charging problem?

Do a diode check for the rectifier. AC voltage across the yellows indicates the stator is OK. If the wiring is OK, the rectifier is the likely culprit. Also, measure voltage across battery terminal with engine running. If not > 13 VDC, the rectifier is suspect if you have 50 VAC to it from the stator.

 

[nahuston]

Re: 90hp v4 charging problem?

Thanks, I have checked voltage with the motor running (at a fast idle) and I get no change. I have read some posts that say that the motor has to run for a substantial amount of time at higher rpms to see a voltage increase at the battery. My experience with every other charging system I have worked with is that even at idle I should see a little more voltage at the battery.

 

[wilde1j]

Re: 90hp v4 charging problem?

Not so. Some voltage above nominal static voltage of 12.7 vdc should be seen right away. Some of the older, 6A charging systems appeared slow, only because they produced so little charge, especially if there was any load.