1984 Johnson 150hp Charging Problem - Strange...

kburks1230

Cadet
Joined
Feb 26, 2008
Messages
10
Here are the facts.

- wide open throttle - only 12.45 volts on my handheld digital testing meter(same voltage at idle)
- batteries aren't charging(they have water and are brand new)
- engine was rebuilt and the charging components look brand new(stator, regulator, wiring, etc.)
- wiring appears to be flawless and connections look good
- tachometer works and reads accurately
- batteries are new
- runs and starts fine

What the heck?... Did the stator or regulator get fried and one needs to be replaced...? Wouldnt' the tachometer be not working properly if this were the case? My tach works perfectly... Any feedback would be very appreciated...
 

blackbox

Seaman
Joined
Feb 24, 2009
Messages
74
Re: 1984 Johnson 150hp Charging Problem - Strange...

if you have good continuity between the two yellow wires from the stator and they are not shorted to grownd, your voltage regulator is probubly bad. the newer ones no longer use a purple "sense" wire and seem to hold up better.
 

Barnacle_Bill

Admiral
Joined
Feb 8, 2004
Messages
6,469
Re: 1984 Johnson 150hp Charging Problem - Strange...

Your rectifier can be bad and the tach still work. It depends on what diodes blow in the bridge rectifier.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 1984 Johnson 150hp Charging Problem - Strange...

Do you have a voltmeter on the dash, or are you just using your handheld one? The voltage you noted on you handheld would appear to be battery voltage. If you measure just after starting, this would be a normal voltage. It could be different after running it for 20 minutes. With a regulator/rectifier, the voltage should creep up to just over 13 after running it a while and the battery gets a chance to charge up.
 
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