charging problem 1979 johnson 100HP

[eaganboater1]

I think i have a charging problem on my 1979 johnson outboard. i'm hoping you can help. here are the symptoms:
the battery has died twice inside of two months, (once leaving me and my daughter stranded on an island in the missippi :<
the tach doesnt work
after running the boat at 3/4 throttle for close to an hour the battery still doesnt take a charge
after putting battery on external charger, it keeps a charge for a month or so
i DID connect the battery with reverse polarity before all this happened and tried starting the motor

i tested the rectifier ( a 3 wire version, 1 red, 2 yellow) as follows
using a multimeter with a diode test setting
connected yellow #1 to red lead, black lead to base overload
" " #2 " " overload
" red wire to red lead, black lead to base - overload

reversed leads
yellow # 1 .518 volt
yellow #2 .481 volt
red overload

is the recifier bad?

 

[dr1553]

Re: charging problem 1979 johnson 100HP

It's my understanding that if you hook up the battery backwards that your rectifier is toast. You can get a Sierra brand aftermarket off of ebay for around $20.

 

[dr1553]

Re: charging problem 1979 johnson 100HP

Here's one on ebay for ya...

http://cgi.ebay.com/ebaymotors/ws/e...0326542991&viewitem=&sspagename=STRK:MEWAX:IT

 

[F_R]

Re: charging problem 1979 johnson 100HP

The tests are:

meter leads to yellow and base. Should show either a high or low reading. Reverse meter leads and result should be opposite from the first.

Repeat with other yellow lead & then reverse the leads

Repeat with meter leads to yellow and red & then reverse the leads

Repeat with other yellow and red & then reverse the leads.

As you can see it must pass all 8 tests. If it doesn't, it is junk.

However, if you connected the battery backwards, save your time. That will instantly destroy one or more of the diodes in the rectifier. You can't disconnect it fast enough to prevent damage.

 

[eaganboater1]

Re: charging problem 1979 johnson 100HP

thank you everyone. i appreciate the help!