Re: 87 25hp evinrude alternator
i have a 25hp electric start evinrude that stopped starting on me. The starter motor pops up but just doesnt have enough juice to turn the motor over. Im only getting 12.07 volts on the battery when the motor is running. Anyone know where the alternator is on these motors or how to test it?
The stator is under the flywheel. The rectifier is external. It is all connected to the black screw-terminal strip.
To test, disconnect all wires from the terminal strip. Then check for continuity between any two of the three wires going to the stator. Should show continuity. Then check for continuity between any one of them and ground. Should be no continuity.
The rectifier has six diodes inside. Each diode should show continuity in one direction only. That means twelve tests for continuity on the rectifier. They are: Between a yellow lead and ground. Repeat for the other yellow leads. Then between a yellow lead and the red lead. Repeat for the other yellow leads.
The final test makes sure it is all connected to the battery. Check voltage on the red lead that connects to the rectifier's red lead, and ground. Should show battery voltage.
Before putting it back into service, remove, and clean battery connections shiny bright, and inspect battery cables. A poor or corroded connection is probably what blew the rectifier in the first place and will blow another one if not corrected. OR, connecting the battery backwards will blow it instantaneously.