connecting 2 wires from alt from outboard

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Mar 24, 2012
4
Mac 25 Bristol
I have an Evinrude 8 hp outboard with two wires coming from the Alternator. The wires are not connected to the battery, this is a boat I just purchased. My question is does one wire get connected to the positive and the other to the negitive post on the battery
 

kenn

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Apr 18, 2009
1,271
CL Sandpiper 565 Toronto
You say 'alternator'... do you mean a separate geared unit, or a coil under the flywheel?

I strongly recommend hooking a 12 lightbulb across the wires coming from the engine and if the bulb lights (engine running of course) then measure the voltage on the bulb with a multimeter to see if it's DC or AC.

Our 5HP outboard has a coil but it was intended to provide up to 5 or 6 amps into boat lights only, so there's no rectifiers; it's just AC. Of course a bridge rectifier can be added to create DC.

I've yet to go to the effort of adapting our outboard for charging, and now that I've got a 6w solar panel for trickle charging, it might not be that useful.
 
Mar 6, 2008
1,311
Catalina 1999 C36 MKII #1787 Coyote Point Marina, CA.
I had not given this much thought - but My outboard engine had two wires that I directly connected to the battery. It had an electric starter and it was also the charger for the battery. It put out 6 AMPS. Worked just fine. I had no external charging circuit.
 

Sumner

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Jan 31, 2009
5,254
Macgregor & Endeavour 26S and 37 Utah's Canyon Country
I had not given this much thought - but My outboard engine had two wires that I directly connected to the battery. It had an electric starter and it was also the charger for the battery. It put out 6 AMPS. Worked just fine. I had no external charging circuit.
Same with us. The batteries are forward in the boat so we had to go with a heavier gauge wire, #4, all the way to the batteries to account for the run length and the fact that it takes more amps to start the outboard, 9.8 HP Tohatsu, than it puts out.

More here...

http://purplesagetradingpost.com/sumner/macgregor2/inside-30.html

Sum

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Mar 24, 2012
4
Mac 25 Bristol
Does it mater which wire gets connected to the + side of the battery? Both wires coming form the engine are black.
 
Feb 26, 2004
23,008
Catalina 34 224 Maple Bay, BC, Canada
It SURE does. Have you tried opein up the cowl and seeing if they are identified inside the engine?
 
Apr 8, 2010
1,606
Frers 33 41426 Westport, CT
Was your tohatsu an older 2 stroke? Our year old 4 stroke 9 hp seems to charge just fine with solar panels.

Sum

Yes, my understanding is that the 4 strokes have proper regulated outputs on them from the factory, the 2 strokes never did. This applies to most manufacturers not just Tohatsu / Nissan / Mercury
 
Jun 8, 2004
10,400
-na -NA Anywhere USA
Pelher;

You did not give us enough information to properly answer. Is your engine electric start? Generally if there are wires comeing from the engine for an 8 hp motor, it is electric start. That being the case, the two wires are either color coded for example red for positive with black for negative. In some, one of the black wires may be colored coded white which is for the positive. That being said, the positive should go to the positive side of the battery; otherwise, you could damage the alternator and/or battery if cross wired.

If the cables are thick and it is electic start, for quick connect/disconnect, use of a two plug trolling motor plugs is ok to use but make sure of your wiring connections that red goes to the plus side of the battery. Also use minimum of # 6 cable from the plug to the battery is a must as the electric start pulls alot of power. Thinnk of heat going thru a large cable vs a very small cable. the very small cable will burn up for example a #18 wire will burn up.
 
Feb 20, 2011
8,058
Island Packet 35 Tucson, AZ/San Carlos, MX
If your set-up is anything like mine, there's a fused wire coming off the rectifier. That's my hot(red) wire.
 
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