88 evinrude 50 not charging

[steelespike]

I'm a little weak understanding the charging system on my 88 Erude 50.
Owned since new sold to a friend this summer all working fine but not charging 12volts cruising at 4,000.Tach works He has only done a very superficial check for loose wires to this point. I thought if tach works it should charge?? unless a bad connection or other simple problem.Anything he can check before he takes it for repair?

 

[Vic.S]

Re: 88 evinrude 50 not charging

really needs a systematic check all the way through
1. Continuity of stator coils
2. AC output from stator coils (yellow/gray to yellow and yellow/gray to yellow/blue)
3. DC output from rectifier (ground to red wire)
4. Volts measured at battery

1. With them disconnected you should find continuity between all three yellows coming from the stator (but twice the resistance between yellow and yellow/blue as between other combinations)

2. Should easily get well in excess of 12 volts AC, rising with revs between the pairs above (dont know what you get between yellow and yellow/blue though)

3. DC output should also rise well above 12volts as the revs increase Measure with the red disconnected (but disconnect while not running)

4. With the red reconnected volts should rise above 12 volts as the battery charges. (With a non regulated rectifier it might get higher than you expected!)

The rectifier can be checked if suspect by following Joe Reeves' instructions

http://forums.iboats.com/showthread.php?t=190638

but if you use a digital meter use the diode test range not one of the ohms ranges.

If the battery has ever been connected with the polarity reversed the rectifier would have instantly blown.