1989 Johnson 48 low voltage

[nashville_roy]

My original problem was the tachometer not working. Using some of the information in this forum, I found that the rectifier was open. I also noticed that the voltage across the battery only varies from 12.6 to 12.7 from idle all the way to WOT.<br /> After replacing the rectifier, the tach is now working but the voltage situation has not changed. Any suggestions where to look next?

 

[duke3]

Re: 1989 Johnson 48 low voltage

Hello nashville_roy<br /><br />If your battery is too old, or have been dry, then change it.

 

[angus63]

Re: 1989 Johnson 48 low voltage

Welcome Roy<br />I suspect your stator has both ignition and charge coils, and the charge ones have an issue. Use the factory manual to troubleshoot the ignition components (try stator charge coil ohm test first) to determine if this in fact is the issue. I am assuming that all of the connections are correct and clean first.<br />Good luck

 

[nashville_roy]

Re: 1989 Johnson 48 low voltage

The battery should be in good shape. It was purchased last fall and still charged when I bought the boat in July. I trickle charged it and used it every weekend for a month before I bothered to try and fix the tach problem. I had cleaned all the terminals before I took it on the lake because I didn't like the way the guy who had it before me wired the radio and I cleaned up some of the mess.<br /> I bought the Clymer Marine Repair Series book for the motor and it has been somewhat helpful...but I am confused about the stator and the charge coil. I did what the book called a stator check of the three yellow wires and the ohm readings were out of tolerance by about 1/2 an ohm. When I look up the stator part number ( it doesn't seem to be available on this site for my engine), it shows a stator coil with two brown wires.<br /> Last but not least of my confusions is what I read in one of the posts of this forum is that the charge coil is to charge the ignition coil and that the stator was to charge the battery.<br /> I guess my question is - is the rectifier output used for charging the battery? If so, which coil is feeding it and how many leads does it have?<br /> "Who's on first? - I dunno...Third Base!"

 

[nashville_roy]

Re: 1989 Johnson 48 low voltage

OK...so I was impatient. <br /><br />I posted my last note at lunch from my office. After getting home, I got out the book (still not much help with wiring diagrams) and started looking around for damaged wiring. The voltage started creeping up and was up to about 13.3 at high idle. I'll double check the water level in the battery and see what it does this weekend. I'm a little leary of putting the charger on it with the new rectifier.<br /><br />Thanks for the help!

 

[duke3]

Re: 1989 Johnson 48 low voltage

Hello Roy.<br /><br />your rectifier are only used for changing the alternating current to direct current. Your rectifier hase 4 wirers. Im not sure, but one off the wirers should be black ( for ground), one should be red or red/white ( +12V Battery) and two (broun) should go to stator-coil part no 583485 if you take a look at this link.<br /> http://ishopmarine.com/ishop/jsp/As...~A0000021~M0010086~M0010167~M0010168~C0141617 <br /><br />Anyway, nothing will happens to your new rectifier, if you put a charger on the battery. But dont start the motor, while you are charging it.