68 Johnson 100HP won't charge

[windchill]

I have a 1968 100 Horsepower Johnson that shows a discharge on the ammeter under power. In the past a new rectifier has solved the problem, but not this time. I've tried 2 new rectifiers to no avail.

Anyone have any suggestions ?

Thanks

 

[Barnacle_Bill]

Re: 68 Johnson 100HP won't charge

If you have a 15amp system you have a regulator. If not you have a 9 amp system. Either way you can check the stator (2 yellow leads) with an ohm meter. A 9 amp should read about .75 ohms and a 15 amp about .4 ohms. Hope that helps. I'm assuming you have checked all connections to be sure they are clean and tight.

 

[windchill]

Re: 68 Johnson 100HP won't charge

Thanks for the reply.
It is a 15 amp system and has a regulator. I'll put a tester on the stator tomorrow.
What about disconnecting the regulator and running the rpm's up briefly to see if the ammeter will show charging?
Does that seem like a plausable diagnostic technique?

 

[Barnacle_Bill]

Re: 68 Johnson 100HP won't charge

That will work. Also you can check the stator output. You should have 12 V AC at each of the yellow leads.

 

[windchill]

Re: 68 Johnson 100HP won't charge

Spent several hours today chasing electrons. Was a bad stator. Open circuit across the yellow leads.

Thanks for the help!