I have an 88 Yamaha 200hp 2 stroke with a charging issue. Dual batteries. Both are known to be good. I have a strong automotive repair background, but don't know a lot about outboards specifically.
Over the course of several hours of low speed (1000 RPM) trolling, it gradually kills a battery. I checked the voltage at the battery terminals with a voltmeter and it shows 12.25v at idle. At 2000+ RPM it increases to around 12.75v. I was expecting something closer to 13.5v+. I've been over all the wiring and connections and everything seems clean and tight.
A took a chance and disconnected 6 wires coming off the stator. I assume it contains 3 coils. (3 pairs of wires) Using an ohmmeter, I found the resistance to be the same on each pair and none of the pairs have continuity to each other. I didn't look at the stator any further. I didn't seem like a likely culprit, but it was an easy test to perform.
I found the rectifier assembly. Are there diodes inside this assembly? Any simple way to test it with a volt meter? Do these go bad frequently?
Any thoughts on what my next step should be?
Over the course of several hours of low speed (1000 RPM) trolling, it gradually kills a battery. I checked the voltage at the battery terminals with a voltmeter and it shows 12.25v at idle. At 2000+ RPM it increases to around 12.75v. I was expecting something closer to 13.5v+. I've been over all the wiring and connections and everything seems clean and tight.
A took a chance and disconnected 6 wires coming off the stator. I assume it contains 3 coils. (3 pairs of wires) Using an ohmmeter, I found the resistance to be the same on each pair and none of the pairs have continuity to each other. I didn't look at the stator any further. I didn't seem like a likely culprit, but it was an easy test to perform.
I found the rectifier assembly. Are there diodes inside this assembly? Any simple way to test it with a volt meter? Do these go bad frequently?
Any thoughts on what my next step should be?