I finally gave in and replaced my 40-year-old steel work boat.

The new boat is powered by a new-old-stock 2001 Mercury 30hp 4-stroke
outboard - carbs, tiller, manual start. Very happy with the performance
and fuel economy :-)

I need to install running lights and I'm hoping the motor has a lighting
or charging coil I can utilise to avoid the hassle of a battery, but the
owner's manual is useless, doesn't even include a wiring diagram. My
motor does not appear on Mercury's web site listing of those for which
an accessory lighting coil is available.

There are two yellow wires which appear to come from the stator, not
connected to anything, just have rubber plugs installed in the
connectors. An analog multimeter reads about 3V DC/25V AC across these
wires at idle. Are these for the charging circuit on the electric start
version? Can I use them to power running lights?

If so, where can I obtain a rectifier/regulator suitable for powering
12V DC running lights, or (better yet) a circuit diagram to make my own?

TIA

Sunny

Yellow wires are typically for the charging circuit on a merc (they are on my
2002 60 4 stroke and my old 89 75hp)

The easiest way to get a rectifier working is to buy the merc unit ($30-40) but
it is basically just a bridge.
You could use one of those square block diode bridges if it was good for 20a or
so. The 50a ones show up on surplus sites pretty cheap.

The problem is without a battery I am not sure how you regulate the viltage.

Greg wrote:
Yellow wires are typically for the charging circuit on a merc (they are on my
2002 60 4 stroke and my old 89 75hp)

So I have probably found the correct wires....

The easiest way to get a rectifier working is to buy the merc unit ($30-40) but
it is basically just a bridge.
You could use one of those square block diode bridges if it was good for 20a or
so. The 50a ones show up on surplus sites pretty cheap.

Sounds like more than I need - running lights will not draw more than
5A, so a bridge made from 4 x 30 cent diodes should be adequate.

The problem is without a battery I am not sure how you regulate the viltage.

Single chip regulators are available for a buck or two which should do
the job, but I'd be more comfortable if I could find a circuit diagram
which has already been tested and known to work on an outboard...

Thanks for your suggestions.

Sunny

These unregulated charging systems depend on load to keep the voltage down.
They usually put out about 9a at WOT. You can get a 50a bridge for a few bucks,
I will send you one if you want. I have a drawer full.
The 3 terminal regulator might work but be sure it can handle the unregulated
voltage from the alternator. If you could find a 1960-7x? Triumph motorcycle
zener it would solve the problem. I had the same thing with my old 75
merc/mariner. It used to bake batteries.

Don't think "outboard" . You know the AC source, so use a 1/2 wave, full
wave, or bridge with a clamp, to get what you need.

It's still electronics 101 - and no more - no less.

-W

"Sunny" wrote in message
.. .


Greg wrote:
Yellow wires are typically for the charging circuit on a merc (they are
on my
2002 60 4 stroke and my old 89 75hp)

So I have probably found the correct wires....

The easiest way to get a rectifier working is to buy the merc unit
($30-40) but
it is basically just a bridge.
You could use one of those square block diode bridges if it was good for
20a or
so. The 50a ones show up on surplus sites pretty cheap.

Sounds like more than I need - running lights will not draw more than
5A, so a bridge made from 4 x 30 cent diodes should be adequate.

The problem is without a battery I am not sure how you regulate the
viltage.

Single chip regulators are available for a buck or two which should do
the job, but I'd be more comfortable if I could find a circuit diagram
which has already been tested and known to work on an outboard...

Thanks for your suggestions.

Sunny