Charging Issue on 1988 Johnson 90HP

[Roadtrip76]

I have a 1988 Johnson 90HP motor with a strange charging issue. The stator is putting out 20 volts ac at idle, but I am only getting 12 volts at the terminal strip. Tach wasn’t working either, so I jumped the tach wire over to the stator side and it started working. This lead me to believe the regulator/rectifier was bad, so I replaced it today with a new one. Tach still doesn’t work after moving it back to the correct location and I still only have 12 volts.

 

[ct1762@gmail.com]

the stator uses power coils to pump out the juice you need. 12v at the strip is what is needed, so no issues there. how did you get the 20v figure? there isnt a test for those power coils that i'm aware of accept for the newer 60 degree motors, so maybe you were testing the brown/brown yellow wires, which is the charge coil and needs to be 200v++. Replace stator.

 

[Roadtrip76]

the stator uses power coils to pump out the juice you need. 12v at the strip is what is needed, so no issues there. how did you get the 20v figure? there isnt a test for those power coils that i'm aware of accept for the newer 60 degree motors, so maybe you were testing the brown/brown yellow wires, which is the charge coil and needs to be 200v++. Replace stator.

20 volts ac is what I get from the two yellow wires coming from the stator and the voltage increases as the throttle goes up. I’m thinking something must be grounding out somewhere.

 

[ct1762@gmail.com]

yes sounds like the power coils to me, which means new stator. if the wires aren't corroded or chafed, the short is inside the coils somewhere. you can do a ground test with a digital meter.

 

[Roadtrip76]

yes sounds like the power coils to me, which means new stator. if the wires aren't corroded or chafed, the short is inside the coils somewhere. you can do a ground test with a digital meter.

I found the problem after studying the wiring diagram. The purple wire which supplies 12 volt power to to the regulator via the switch was reading zero. I jumpered around it and it started charging.

 

[ct1762@gmail.com]

I found the problem after studying the wiring diagram. The purple wire which supplies 12 volt power to to the regulator via the switch was reading zero. I jumpered around it and it started charging.

isn't the purple wire for the primer and the red wire is 12v in?

 

[ct1762@gmail.com]

come to think of it... the solid purple just goes on the terminal strip not connected to anything else. the purple/white is for the primer. interested to hear how this wire provided power?