Re: [OMC-Boats] Wiring puzzle....

From: Lee Shuster <lks@...>
Date: Sat, 3 Oct 2009 20:20:52 -0600


You are correct in that someone in the past tried to "graft" on older
intermediate and sterndrive into your post-1969 (late model) Evinrude.

You are going to need to use both the wiring diagrams I have posted to
solve or re-construct your wiring maze.

The new version went to the LARGE ROUND YELLOW AND BLACK harness
connectors and did not use the OLD separate terminal strip with
exposed positive and negative high current connections (a safety no-no).

Did the hack leave any parts of the LARGE round connectors on the boat
side? You might want to try and acquire a used post 1969 OMC engine
harness, just to get these Yellow and Black round connectors.
A picture of my 1971 retro fit shows them. I did have the boat harness
from my donor boat so I rewired my entire boat and a year later
installed a new dash.
You can see the two ROUND connectors at the rear of the starter motor.

Old (pre 1969):

New (1969 and newer):

On your alternator the small terminal is (F) for field and the large
terminal is the 8 ga (B) terminal OUTPUT that was later fused. My
Alternator is only externally grounded thru the case and mounting

There are so many things wrong in your picture, that aren't your
fault, I know. But if it were mine I would just rip it all out and
start over. Here's what I spot wrong (I'm sure there could be more):

a) Never use wire nuts. They are prone to coming loose due to shock
and vibration, especially in marine applications. Learn how to use
the proper crimping tools and SEALED MARINE connectors to make safe,
reliable butt connections.
West Marine has good tech articles on this. Notice how the OMC
connectors are sealed, but all the "hacked" ones will allow moisture
in from the wire side collar? Eventually that wire will be exposed to
the elements and it will travel up inside the insulation where you
can't even see it.

b) All of the visible connectors and fasteners have visible corrosion/
oxidation and most likely have measurably high resistance. Yank those
crappy old tilt relays and get brand new ones and use stainless
fasteners. While you're at this winter yank the starter assist relay
(same as tilt relay) as well. I'll bet it's terminals are corroded as

c) Go thru the entire engine area, one wiring subsystem at a time: a)
Stater and assist relay, b) Alternator and regulator, c) instrument
senders, d) Coil/ ballast resistor/Distributor, e) Battery supply and
all grounds, and of course our favorite, the tilt motor and it's relays.

d) Like I suggested above. Start searching for a 1970 to 1977 OMC
engine harness. I wouldn't even be picky about it coming from a Buick
V6 but that would be plug and play as far as fitment. But one could
fairly easily modify a I-4 or V-8 harness to extend or shorten the
lengths to reach various electrical components, but at least you have
those big round (SEALING) connectors.

Bill, I really admire you attitude. Hang in there, man. We've all had
the challenges of bringing back someone else's mistakes. It will make
next season on the more rewarding!


On Oct 3, 2009, at 6:54 PM, BLDFW wrote:

> A continuation of my charging problems.......I've already figured
> out where most of the problem is. And I'm beginning to see why
> someone else's restoration efforts were abandoned years ago. But,
> I'll not be deterred....just stymied by my own ignorance! ;-)
> Check out the attached pic. Anyone care to hazzard a guess as to
> what is wrong with this picture?? It pays to have a good wiring
> diagram (and a good mind......well....maybe). The problem appears
> to have been staring me in the face all along....but I wasn't quite
> "ready" to experience it......yet. Jeesh!
> First off.....the boat was repowered at some point with an earlier
> vintage engine. The wiring harness that came with the engine does
> not match the boat's main harness leading to the front. Now it
> would have been nice if they had replaced the engine harness with
> the original one. It might have gone right back together without a
> sweat but nooooo. Oh well, no accounting for amateurs (uh....myself
> included).
> I can see several jury rigged spots already. The green 8g wire in
> the pic is supposed to feed the tilt solenoids 5 inches away but
> nope, it ends right there. Rather they ran the red wire direct from
> the starter where, coincidentally by design, the other end of the
> green wire originates too. Ain't ignorance bliss.
> The brown 8g wire also goes nowhere....well guess what!!....that is
> the feed directly from the alternator so no wonder why it is not
> charging the battery! It had no where to go too! JEESH! I'll have
> to match it now with the correct wire in the boat harness to get it
> to the dash where it's supposed to go.
> And Finally, the black 8g wire also goes nowhere. That's a ground
> wire. The two black wires attached via the screw to the right which
> holds the block down are supposed to be attached to the black ground
> wire.
> Once I get all that figured out and double check the dash stuff,
> I'll go back and check the alternator again. Ain't it just
> grand....or is that just "another grand"?
> More later.
> -Bill
> Dallas, TX
> 1970 Evinrude Explorer - 155 Buick V6 - OMC Sterndrive
> <Wiring 003.jpg>_______________________________________________
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Received on Saturday, 3 October 2009

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