Unknown wire in 1982 Mariner 40 hp??

[yautja1978]

While servicing our Mariner 40 hp outboard boat motor from -82 (I think) we noticed a red wire that has broken off, and not knowing where it's supposed to go or what it's for, I thought I'd ask here if some kind soul would like to share their knowledge.<br /><br />The wire is red, and attached to a black box located inbetween the starter motor (behind it) and the fuel filter. The box also has two green wires that go up under the main turn wheel and a black one assumed to be ground. The red wire shows some corrosion and has broken off from something. The text on the black box seems to say "STanley DE 4204".<br /><br />Does anyone know what this could be and what it's for? I should probably mention that the motor seems to run fine as far as we can see while still testing it on land. ANY help with this would be greatly appreciated.<br /><br />//Robert in Sweden

 

[yautja1978]

Re: Unknown wire in 1982 Mariner 40 hp??

I'm sorry for doubleposting here but it doesn't seem like anybody will answer and I've searched around a bit more in general on it now, both on and off this forum.<br /><br />My suspicion from what I've read on many motors of various brands is that this suspicious black box is the rectifier, and that the green wires that go up under the fly wheel come from the stator. This would then mean that the red lead coming out of the box is supposed to hook up to the battery cable, for charging.<br /><br />I'm just wondering if anyone can confirm if this is likely to be the case even on a 1982 Mariner 40 hp? I've only found this described for other outboarders, most of which are not nearly as old.<br /><br />//Robert

 

[btatum]

Re: Unknown wire in 1982 Mariner 40 hp??

if it's possible take a pic of the box and related wiring. not positive on the discription you provided.

 

[ronmold]

Re: Unknown wire in 1982 Mariner 40 hp??

Does the motor charge up the battery?

 

[yautja1978]

Re: Unknown wire in 1982 Mariner 40 hp??

In theory, the motor charges the battery. Not sure if it really actually works though, haven't tested it.<br /><br />I took two pictures to better illustrate the part of the engine I'm talking about. In this one you can see the box (marked with red arrow) under which the green wires + red wire comes out of:<br /><br />

<br /><br />And then in this picture you can see on the other side of the motor the same green wires (red arrow) going up under the flywheel.<br /><br />

<br /><br />Any clue what this box is or where the red lead is supposed to go?

 

[btatum]

Re: Unknown wire in 1982 Mariner 40 hp??

from what i can tell from the wiring harness diagrams i have the 2 wires going under the flywheel are going to the stator. the black wire goes to ground and the red wire should lead to the battery. try running a fused jumper from the battery back to the red wire. install muffs and run the engine at a idle. before starting ck battery voltage, then after starting ck voltage again, if the system is working there should be a rise in voltage.<br />as for where the red wire came from or broke i was not able to locate a proper wiring harness for your engine but was able to locate a functional diagram of the charging system.

 

[jasper2447]

Re: Unknown wire in 1982 Mariner 40 hp??

The box is a rectifier - I've just fitted an identical one to my Mariner 15. This engine has a stator (like the al;ternator on a car) under the flywheel which puts out alternating current (AC) and if you want to charge a battery you need to convert it to Direct Current (DC) That is what the rectifier is for - you now should have DC power flowing out of the rectifier with the red lead being positive to the battery + terminal and returning from the negative terminal through the engine casing to earth (ground). You should check this with a voltmeter between the red cable and the engine case and you will find an output voltage of between 10 V at idle to about 18V at full revs - you may need to fit a voltage regulator to limit this top voltage to 14 V or 15V so as not to damage 12V instrumentation run off the battery such as VHF radiio, fishfinder etc.

 

[yautja1978]

Re: Unknown wire in 1982 Mariner 40 hp??

Thanks guys! As I suspected that was it, we hooked the red lead up to the battery, put the boat in the water as everything else was set, and it now runs better than ever before (did some major cleaning up and fiddling with the motor this spring). <br /><br />The charging even seems to work fine, it outputs around 11-12 V at idle and somewhere around 16-17 V at full speed.<br /><br />Thanks a lot!