Johnson 175 charging

[Gary H NC]

I got my 1981 175 put back on the boat and did a test start on the muffs.
Was checking everything over and put the volt meter on the battery.
12.5 volts at idle to 2000 rpm. 12.5 with engine off. I guess its not charging.
Tach is working. Where do i start testing?

 

[HighTrim]

Re: Johnson 175 charging

This was posted by joe a while back but still holds true for your problem, gl

(Small Rectifier Test)
(J. Reeves)

Remove the rectifier wires from the terminal block. Using a ohm meter, connect the black lead of the ohm meter to the rectifier base (ground), then one by one, connect the red lead of the ohm meter to the yellow, yellow/gray, then the red wire (some rectifiers may also have a yellow/blue wire. If so connect to that also). Now, reverse the ohm meter leads and check those same wires again. You should get a reading in one direction, and none at all in the other direction.

Now, connect the black lead of the ohm meter to the red wire. One by one, connect the red lead of the ohm meter to the yellow, yellow/gray, and if present, the yellow/blue wire. Then reverse the leads, checking the wires again. Once more, you should get a reading in one direction and none in the other.

Note that the reading obtained from the red rectifier wire will be lower then what is obtained from the other wires.

Any deviation from the "Reading", "No Reading" as above indicates a faulty rectifier. Note that a rectifier will not tolerate reverse polarity. Simply touching the battery with the cables in the reverse order or hooking up a battery charger backwards will blow the diodes in the rectifier assy immediately.

 

[Gary H NC]

Re: Johnson 175 charging

Thanks,will give it the test tomorrow.

 

[Gary H NC]

Re: Johnson 175 charging

Ok,the test shows no reading in either direction.
With the red lead on the ohm meter touching ground then the black lead on the meter touching each wire i get a reading for a split second then back to 0..?