ammeter for 69' 85 hp

sbrice

Cadet
Joined
Sep 12, 2002
Messages
13
I would like to add an ammeter to my 69' 85 hp.<br />Is it necessary to run wire all the way to the<br />starter solonoid or is there provision in the<br />control bundle?<br />Would a voltmeter be a better addition? I'm just<br />interested in knowing that the alternator is working<br />okay.
 

Skyhigh

Petty Officer 2nd Class
Joined
Jul 25, 2003
Messages
131
Re: ammeter for 69' 85 hp

I was wondering the same thing, so I got me a voltmeter and ran the wires from the battery and the control box. I connected it with a 2-way switch so I can check both. Then I thought if the alternator stoped working shouldn’t the gauges stop working?
 

mrc

Petty Officer 2nd Class
Joined
Dec 8, 2001
Messages
149
Re: ammeter for 69' 85 hp

I have done this with the aid of the service manual<br />to my 85hp Johnson, 1970 (pretty much same as your 69)<br /><br />You do not need to run an additional wire to the <br />instrument panel, all the wires are there to do<br />it. There is a little bit of rewiring to do<br />in order to accomplish this.<br /><br />There is two red wires that connect to the starter<br />solinoid via a single screw on connector. <br />Disconnect this connector and seal it off with<br />electrical tape. This will put the voltage from <br />the alternator through the red wire to the <br />ignition switch. Now disconnect the red wire<br />from the ignition switch and connect it to the ammeter.<br />Run the other wire from the ammeter to the screw connector which the red wire was previously connected.<br /><br />This will effectivly show the current going into/<br />out-of the battery. So if the alternator is <br />putting out 9Amps of current, but the ignition<br />is drawing 5 amps. Your ammeter will show 4 amps.<br />The starter current draw is not represented on<br />the ammeter (Nor would you want it to be shown)<br /><br />There will some voltage drop on the charging current, but with an unregulated charging circuit<br />this is not really a problem.<br /><br />If you can find a +/- 30amp meter it will be more<br />usefull than the +/- 60amp which is typical. Your motor has a 9amp alternater which after supplying<br />current for the ignition, will barely deflect the<br />60amp meter.<br /><br />I also have a voltmeter installed, and each has it's<br />role. <br /><br />Regards,<br />Michael Carney
 

sbrice

Cadet
Joined
Sep 12, 2002
Messages
13
Re: ammeter for 69' 85 hp

So your saying that I only need to run one long<br />wire from the ammeter back to the starter solenoid?
 

mrc

Petty Officer 2nd Class
Joined
Dec 8, 2001
Messages
149
Re: ammeter for 69' 85 hp

Oops, sorry I wasn't too clear.<br /><br />In an unmodified configuration, there is the<br />big heavy gauge red wire which runs from the<br />battery to the starter solinoid. Off of that same<br />terminal on the starter solinoid is two wires.<br />One goes to the ignition switch, and one goes<br />to the recifier, and subsequently to the alternator.<br /><br />You will be removing those two wires from starter<br />solinoid (but leave them connected togeather) and <br />thus the direct connection to the battery. At <br />that point you will have direct connection from <br />the alternator/rectifier to the ignition switch <br />in the existing wireing harness.<br /><br />You need to run a 12 guage or better wire from the <br />+ terminal of the battery to one connection of<br />the ammeter. Then jumper the ammeter other terminal<br />to the same terminal on the ignition switch<br />as the red wire.<br /><br />PS. What I ended up doing was run an 8 guage<br />wire fused at the battery for 40 amps to the<br />ammeter, and the from the ammeter to a distribution<br />fuse panel. Then I jumpered the red ignition <br />switch wire to the fuse panel with a 10 amp<br />fuse installed. Other accesories (such as running<br />lights, horn, hydrolic tilt, & radio/fish finder<br />all attached to different fuses on the panel.<br /><br />Configured in this manner, the ammeter is ALWAYS<br />active and displaying any draw (outside of the<br />starter motor) on the battery (well almost true,<br />the shift solinoids draw some current off of<br />the alternator during wind-down after shutting<br />off the motor, in order to keep the lower unit<br />in nuetral)<br /><br />The guage of the wiring running from the battery<br />to the ammeter is dependent on how many other<br />loads you have on the battery... Due to the<br />hydrolic tilt, I ran 8 guage rather than 12.<br />But if you are just doing running lights and<br />the ignition current, 12 guague would be fine.<br /><br />The alternator puts out 9 amps, but will never<br />charge at that rate... probably 4-5 amp charge<br />is more typical.<br /><br />Regards,<br />Mike
 
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