Charging / Tach Prob. Rectifier?

[Bryant Davis]

I have a 1982 Johnson 150. Recently, and only at high speeds / rpm's the Tach will zero out. I noticed yesterday that at the same time the tach was reading zero, my voltage gauge (that I connected directly to the battery) was reading 16 volts. When I slowed down, both gauges returned to normal. Does this sound like a rectifier problem? Also I noticed that while my tach was reading zero, that if I pushed the trim up or down button I would make the needle bounce around.<br /><br />Bryant

 

[TX Duck Guy]

Re: Charging / Tach Prob. Rectifier?

Sorry I can't help on your problem exactly, but I do know that 16v is WAY too much to be sending to a 12v battery to charge it. Typically it's more like 13.8v output to battery. I believe you are in the right place though. Maybe at high rpm where the voltage output from the alternator is highest the rectifier is "leaking" voltage and can't quite handle the output. Perhaps your local marine shop has a test fixture for these parts.

 

[rickdb1boat]

Re: Charging / Tach Prob. Rectifier?

Check your rectifier connections. Sounds like a loose connection somewhere. Check the ground real good..