1979 85 johnson over charging

[wayneo99]

1979 85 Johnson runs great no performance issues at all

recently I was have charging issues did some diagnostics after reading some similar issues here on the forum.

both batteries are new in may running a typical dual batt switch

stator is putting out 20 VAC, impedence tests are good

non water cooled round 3 wire rectifier tested bad, new one from omc dealer 3 wks ago

charging was fair about 13.33 volts, every thing was going good.

last trip out volt meter was reading 17 volts on batt #1, double checked with my digital meter.

switch to battery #2 and back to 13.33, switch to "both" 13.33, back to #1 and 15-17volts

the tach was also intermittant, switched the gray wire to the opposite stator wire and it now works.

I cleaned all the batt connections on engine and batt, have to do the batt switch.

rechecked all the rectifier connections, stator output and seem to be testing as normal.
I have not re tested the rectifier diodes

maybe a diode in the rectifier is blown?

how hot is the rectifier supposed to be, its HOT, engine is running correct temp and heads are ok

if these older systems are unregulated what prevents the overcharge condition?

thanks

 

[wayneo99]

Re: 1979 85 johnson over charging

ttt

 

[HighTrim]

Re: 1979 85 johnson over charging

Disconnect the rectifier until you resolve the issue.

Start by testing it, if you need help with this let us know.

 

[Vic.S]

Re: 1979 85 johnson over charging

As you are aware the engine has a simple non regulated rectifier

What you are seeing is therefore not entirely unexpected and blown diodes in the rectifier will not cause the problem

Your no 1 battery seems to have some resistance to charging. All OK on no2 battery. Check the connections again to the no1 battery but if it starts the engine OK you are not likely to find any problem



As you know the non regulated type can be tested if necessary by following Joe Reeves' instructions http://forums.iboats.com/showthread.php?t=190638 BUT if you use a digital meter use one with a diode test facility because they do not all work on the ohms ranges for diode testing.