Make my own internal engine harness; Weatherpack connectors?

[ajgraz]

This is more about wiring than about the motor, but I figured this was the best subforum for this...

1979 3 cyl 70hp Mercury on a 15' trihull. Run in saltwater. I have had to patch up the aging, corroding internal engine harness more times than I can count, and am getting fed up with that. Final straw is that there is now an intermittent short inside the female connector.

This is kind of a bastard-child Merc connector, only used on 1977-1979 3 cyl motors. Exact OEM replacement is high-priced new and hard-to-find used in decent shape, and AFAIK no one (like CDI) makes an aftermarket replacement.

Anyways, I'm ready to make my own internal harness for this motor. Shouldn't be too difficult, I don't think; just wires and ring terminals:

Already planning on Ancor marine wire (10-12AWG red, 14-16AWG all others) and heat-shrink butts and terminals as I already have most of what I'd need; but I don't want to spend $$$ on (CDI) "universal" boat harness/connectors if I can avoid it.

So here's my questions:

1) What kind of connector(s)?
Any reason I should not use automotive GM / Delphi / Packard Weatherpack connectors between the internal and external harness?:
http://www.weatherpack.com/

Would like to use these because I already have all that for automotive work. Also I can do a better job wiring in my jury-rigged add-on temperature sender. Any better suggestion for inexpensive connector(s)?

2) Where should I put the connectors?
Current OEM connection is inside the motor cowling, bolted to the side of the head. I may bolt the cut-off OEM connector back in place, because it is molded so as to also guide/hold the battery cable into the cowling. Also, I do not want to have to extend the external harness. So my choices for where to put the Weatherpacks are:

a) about 4 to 6 inches outside the cowling (basically hanging "free air" above the splashwell; will get splashed)
b) about 2-3 feet outside the cowling (where I can hide them up under the stern cap, although now they're in the same space as where the vented portable fuel tank goes)
c) halfway to the control box, where they are tucked under the gunwales with all the other supported wiring and control cables (no splash, no gas fumes).

Which location would you choose, and why?

 

[achris]

Re: Make my own internal engine harness; Weatherpack connectors?

Your circuit drawing is spot on. The harnesses were a fixed length and usually too long for most applications. I'd be surprised if you don't have some slack somewhere.

I'd be aiming to put the connector inside the engine cowl. If it absolutely must be outside, go for somewhere dry.

The connectors you're looking at look great, just make sure they are 600v+ rated. The kill wire (orange) has at least 400volts on it. These are the connectors Merc are currently using on Mercruiser engine harnesses, so a good choice.

Chris......

 

[ajgraz]

Re: Make my own internal engine harness; Weatherpack connectors?

I'd be aiming to put the connector inside the engine cowl. If it absolutely must be outside, go for somewhere dry.

The connectors you're looking at look great, just make sure they are 600v+ rated. The kill wire (orange) has at least 400volts on it. These are the connectors Merc are currently using on Mercruiser engine harnesses, so a good choice.

Chris......

The more I think about it, the more I think I may put the connectors 1/3-1/2 of the way to the control box, so all the wiring is supported to both sides of the connectors, and the connectors are protected from any splashing.

So the kill wire, does it simply drain to ground the stored voltage in the switchbox (from the stator)? So that'd be AC voltage, yes? Always wondered exactly how the kill circuit worked.

 

[j_martin]

Re: Make my own internal engine harness; Weatherpack connectors?

When I make marine wiring, I use the heat shrink connector. Then I cut away just enough heat shrink so the terminal end of the barrel is open. I strip the wire to be used, tin it if it isn't tinned already, then chuck it up in a holding device so it's vertical. I set the terminal on it, heat it up with a soldering iron and flow rosin core solder into the barrel. There's a learned trick to the temp and timing, and if you do it right, the heat shrink will flow right back over the end of the barrel. Then I finish the rest of the shrinking with a heat gun.

For larger connectors I use a bare connector, solder it on, and insulate it with adhesive lined heat shrink.

These are the terminals I use. The insulation is called semi-rigid polyolefin.
http://www.fastenal.com/web/products.ex?N=999601350+1199904575&Nty=0


Double crimp and pin crimp connectors give trouble in marine service. I don't think you can rely on a squish crimp for anything on a boat.

hope it helps
John

 

[achris]

Re: Make my own internal engine harness; Weatherpack connectors?

So the kill wire, does it simply drain to ground the stored voltage in the switchbox (from the stator)? So that'd be AC voltage, yes? Always wondered exactly how the kill circuit worked.

It effectively shorts the switchbox internal capacitor to ground. The voltage on the kill wire is DC, and it hurts!!

....

For larger connectors I use a bare connector, solder it on, and insulate it with adhesive lined heat shrink.

Double crimp and pin crimp connectors give trouble in marine service. I don't think you can rely on a squish crimp for anything on a boat.

There was a discussion a while back in the Electrical forum where I suggested that only soldering should be used in a boat, and got right royally jumped all over for it!!! Where were you when I needed you???

Chris.....

 

[j_martin]

Re: Make my own internal engine harness; Weatherpack connectors?

It effectively shorts the switchbox internal capacitor to ground. The voltage on the kill wire is DC, and it hurts!!



There was a discussion a while back in the Electrical forum where I suggested that only soldering should be used in a boat, and got right royally jumped all over for it!!! Where were you when I needed you???

Chris.....

Probably soldering a wire on my boat.

 

[earringboy]

Re: Make my own internal engine harness; Weatherpack connectors?

If you have enough wire on the boat side harness why not cut the plug off, push it through the cowl and put your ring terminals right on ther end? You will have no splices or plugs, just one end at the key and the other under the hood. I have a 90hp Merc that this has been done to. All the wire colors should be correct then, and you don't have to hide anything.

 

[ajgraz]

Re: Make my own internal engine harness; Weatherpack connectors?

If you have enough wire on the boat side harness why not cut the plug off, push it through the cowl and put your ring terminals right on ther end? You will have no splices or plugs, just one end at the key and the other under the hood. I have a 90hp Merc that this has been done to. All the wire colors should be correct then, and you don't have to hide anything.

There's not enough wire on the boat side (external) harness to do that. Besides, I like the idea of having connector(s) in the line so that I can remove the control box without having to remove the internal harness from the motor. "Hide" was maybe not my best choice of word re: the connectors, more like "protect" or "keep out of harm's way."

-------------------

j-martin, I am sure your connections are flawless but...

The ring terminals on my original OEM internal harness are all simply crimped on, without even any heat shrink...they've held up for over 30 years apparently. As achris says, Mercury Marine lately uses weatherpack connectors in their engine harness applications. I've never had a properly supported crimp-and-heatshrink terminal fail; the failure here is in the OEM, plastic-encased, soldered-pin connector of all places.

So far I see no reasons to change my plans, in fact I am more encouraged. I understand what you're saying about the double crimp pins in the weatherpacks, but I now intend to make sure the harness is supported by cable clamps on either side of the connectors so that there is no stress or movement there.

 

[ENSIGN]

Re: Make my own internal engine harness; Weatherpack connectors?

Just remember to document and lable all your splices for future referance

 

[j_martin]

Re: Make my own internal engine harness; Weatherpack connectors?

There's not enough wire on the boat side (external) harness to do that. Besides, I like the idea of having connector(s) in the line so that I can remove the control box without having to remove the internal harness from the motor. "Hide" was maybe not my best choice of word re: the connectors, more like "protect" or "keep out of harm's way."

-------------------

j-martin, I am sure your connections are flawless but...

The ring terminals on my original OEM internal harness are all simply crimped on, without even any heat shrink...they've held up for over 30 years apparently. As achris says, Mercury Marine lately uses weatherpack connectors in their engine harness applications. I've never had a properly supported crimp-and-heatshrink terminal fail; the failure here is in the OEM, plastic-encased, soldered-pin connector of all places.

So far I see no reasons to change my plans, in fact I am more encouraged. I understand what you're saying about the double crimp pins in the weatherpacks, but I now intend to make sure the harness is supported by cable clamps on either side of the connectors so that there is no stress or movement there.

Those original crimps are gas tight crimps like the weatherpack connectors that drive multiple fingers into and between the strands of the conductor, and have a separate insulation holder that grips it evenly all around, not just on 2 sides.

Weatherpack adds sealing and usually a dielectric sealing grease.

All of that is in a whole 'nother world from the normal hardware store barrel crimp connector we all know of.

Solder, under some environmental conditions, will actually fail quicker than a good mechanical crimp. Weatherpack falls into the good category.

Solder and weatherproof insulation is about as good as it gets under normal conditions. Especially with inexpensive components and tools.

Yer good to go. Execute your plan.

My 02
John

 

[ajgraz]

Re: Make my own internal engine harness; Weatherpack connectors?

If you have enough wire on the boat side harness why not cut the plug off, push it through the cowl and put your ring terminals right on ther end? You will have no splices or plugs, just one end at the key and the other under the hood. I have a 90hp Merc that this has been done to. All the wire colors should be correct then, and you don't have to hide anything.

Turns out there was another 3' of boat harness coiled up under the stern cap, so ultimately I decided to do just what you suggested:

All ring terminals and three-way butts crimped and using adhesive heat shrink. Three-way butts then covered in two coats of Plasti-Dip. Rubber terminal covers recycled from old harness. I'm going to wrap this in spiral conduit.

Let's see corrosion get me now!

 

[earringboy]

Re: Make my own internal engine harness; Weatherpack connectors?

Ahh, your new harness looks real nice. I found with my 90 just having the colors be right is very helpful when hooking everything up, plus with less connections there is less to check if something is not working right. Looks good.

 

[ajgraz]

Re: Make my own internal engine harness; Weatherpack connectors?

Re-jiggered harness works well:

Did wind up installing an extra wire with a single weatherpack for my temp sensor: