1977 Johnson 115 HP not charging

ngimpel

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Joined
Jun 20, 2011
Messages
18
The charging system is putting out 12.2 volts and will not go any higher when I increase the throttle. I replaced the rectifier. Still the same. Cleaned all connections. I tried to check the AC voltage from the stator while the motor was running, the gauge on the meter would only keep flashing. I thought I might have had a broken stator wire. I removed stator and bench tested it. Using a OHM meter I have continuity from both yellow starter wires. I tested both the new and old rectifiers and got the same readings. My question is should I put it back together and see if it is charging or can anyone lead me in the right direction. The engine runs great other than no charge, Also can someone tell me the correct torque for the fly wheel nut. Thanks.
 

F_R

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Jul 7, 2006
Messages
28,195
Flywheel nut 100-105 ft/lbs.

Are you doing all 8 tests on the rectifier? It is the most likely cause of a non-charge condition. Stator appears to be ok. If not the rectifier, then an open circuit between there and battery?? Or bad ground, corroded battery cable connections??
 

ngimpel

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Jun 20, 2011
Messages
18
Thank You for the reply. The rectifier is new. I did not know there were 8 test that could be done. I ordered the engine book last week, it should be here tomorrow. Does the current that is being produced to recharge the battery travel back through the positive cable or should I be looking for a second wire that should be attached at the battery. I will check each cable to make sure they are good. I did clean all connections. I think I will reinstall everything and start over testing while the engine is running. Thank You again for taking time to help me.
 

ngimpel

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Jun 20, 2011
Messages
18
I just put everything back together. Started engine 12.5 volts at battery at any RPM. I tried to test AC voltage at stator wires but the numbers would not stay constant. Just flashed so fast I could not read them. Tried to check DC voltage at rectifier same thing. I cleaned the inside of the fly wheel be fore I reinstalled it. Just cleaned the ground wire. I'll have to wait until I get the book for this engine. Thank You for your help.
 

F_R

Supreme Mariner
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Jul 7, 2006
Messages
28,195
With all your testing, by any chance have you ran the motor with the battery or rectifier disconnected? That can blow the rectifier----even the new one---instantly. To answer your other question, the red rectifier wire ultimately goes to the positive battery cable at the rectifier. If it is loose or damaged, it is the same as if the battery were disconnected and will blow the rectifier.

When you get your book, check the rectifier (all 8 tests). It must pass all 8 or it won't charge. If it fails, do not install a new one without being absolutely sure of the wiring and connections
 

ngimpel

Cadet
Joined
Jun 20, 2011
Messages
18
Thank You F_R for your help. I did not run the engine with anything disconnected. After I posted my problem about not getting a reading on the meter I remembered that I need a peak voltage tester or an DC voltage adapter. I will try to get one today. Thank You for your help. Every connection have ben cleaned. I'm leaning toward a bad rectifier even if it was purchased as new. I check when I get the book. Today looks like a good beach day here in North Wildwood NJ. Thanks again.
 
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