I get 30+ Volts out of the mag with meter across both ends of the circuit, but the voltage out of the center terminal on the rectifier does not seem to rise above battery voltage. I purchased a new rectifier with the same result. What confuses me is when bench testing either the original or the new rectifier I get the same readings, from one of the "A" terminals to the "B+" terminals I get zero ohms with the meter leads either polarity. On the other "A" terminal to the "B" terminal I get infinity, either polarity. In reading earlier posts with a similar not charging problem, one poster said the rectifier has to be grounded. I tried grounding the original rectifier body momentarily and got a heck of a spark. There was never any ground wire originally.
I guess what I would have expected on a bench test was from either "A" terminal to the "B+" terminal I would have low resistance with the meter leads one way and infinity the other way, but clearly I am lacking understanding of the charging system. Any help appreciated.
Dixie some of the engines had a ground wire from one rectifier screw to blower housing mount covers, Others had a grounding strap that went from the rectifier mounting screw to the blower cover mounting bolt. And your reading went you went from the other A terminal to the B terminal and got infinity but 0 ohms for the other A terminal to B is not unusual for a half wave rectifier.
the rectifier body has to be grounded and battery voltage has to be present at the B terminal to close the internal switch to allow it to charge the battery.
Thanks to R and I for the responses. I am confused however regarding the requirement for a ground wire. I am the original owner - no ground wire! I will report back on how I make out.
#5
Fish
Here is a pic of a Kohler. It is just a small jumper that connects the body of the module to the block.
Feeling pretty stupid at this point, I installed ground wire and all is good. I must have been before the last mowing season I had the housing off. Must have misplaced the ground wire. I did not make any connection to having the housing off because I mowed all summer and it was not till end of summer I started to have a dead battery. How the battery held up that long, that many starting cycles I do not know. I am well past 80, so I'll use that for an excuse!
Fish, thanks for the great pic. And Rivets for the manual link, sure to be useful. and Ilengine for the good explanation.
