build a wiring harness?

[sundog]

anybody done this? I mean, its just a bunch of wires, isnt it, or is there something more to it? do they make aftermarket external harnesses and how much are they? On that topic, is there a way to test the old external harness to see if thats my problem? Ive tried everything else, its got to be in there somewhere (no start, no click, new soleniod, new key switch, OK neutral switch, but engine starts if I jump the starter). 1978 1150 inline 6 merc

 

[Nos4r2]

Re: build a wiring harness?

I built a new harness from scratch for my merc 50 using a Suzuki push-choke ignition. It took about 6 hours and works perfectly-but from what you're saying what you really need to do is test for continuity with an ohm-meter along all the wires in your existing harness. You might just have one wire with an internal break that you can replace external to the harness-or a bad plug.

 

[Chris1956]

Re: build a wiring harness?

Sundog, Aftermarket Engine wiring Harnesses are about $100 for that motor, and are available from several places on the net. Look around for the best price. Boat wiring harnesses are not as popular, and you may need to visit a junk yard to get one. The hard part about making your own are the molded rubber engine connectors. if you do make your own, be sure to use the correct gauge wire.

 

[Laddies]

Re: build a wiring harness?

Engine and outboard harnesses are available thru Rapair Electronics/CDI

 

[ZmOz]

Re: build a wiring harness?

I'm doing the same thing for my inline 6. Tired of fixing crumbling wires, so I just bought about 100' of wire, some terminals, and some heat shrink tubing for less than $20. $100+ for an internal harness and another $100+ for the external harness is ridiculous...

 

[sundog]

Re: build a wiring harness?

OK, paid a guy to check my starting problem, and he says its the external wiring harness. The merc harness is running for about $200. Im going to try to do what Chris mentioned first (find the bad wire and run it external to the harness). After that Id like to try to build one. <br /><br />Id like to keep the old molded rubber connector...any problem with me cutting the connecter off maybe 6"-1' from the plug and (so long as those 6" wires are good) splicing, waterproofing and wrapping in the other wires at that point? what gage/type wire should I use?<br /><br />thanks!

 

[Silvertip]

Re: build a wiring harness?

If you pay attention to wire size and use the same colors you should have no problem. When you cut the plugs off, don't cut all the wires at once -- stagger the cuts so you don't end up with all the splices in the same place (e.g. a big ball in your harness). But why not do as was suggested -- do an end-to-end test with an ohm meter to find the open wire. You might even check the connectors carefully as they may not be making contact. You therefore spend a lot of time making a new harness only to still have a bad one due to bad connectors.

 

[ZmOz]

Re: build a wiring harness?

Originally posted by sundog:<br />Id like to keep the old molded rubber connector...any problem with me cutting the connecter off maybe 6"-1' from the plug and (so long as those 6" wires are good) splicing, waterproofing and wrapping in the other wires at that point? what gage/type wire should I use?<br />

The problem I found with mine was that even where the cable looked to be in good condition, the wires inside were still corroded when I cut it open, which will probably be the same for you. I used 14 gauge, which looks like the stock wire.

 

[sundog]

Re: build a wiring harness?

Ill try to find the open wire first and re-run it. Ive polished the connector as well as I can, but its molded on and theres now way to check the actual wire connections without cutting open the plug. if its still not working, Ill cut the off plug and splice a new harness in, and if its STILL not working, itll be the plug and Ill have to find a way to wire the motor direct, I guess.<br /><br />Ill let you guys know how it goes.

 

[Silvertip]

Re: build a wiring harness?

Yes you can check connections without cutting the plug open. Disconnect the cable at both ends. Connect one lead of the ohm meter to any wire. Connect the other lead to the corresponding pin in the plug. Continuity = a good wire. Open = bad connection or broken wire. Repeat the process for each wire in the harness.

 

[timmathis]

Re: build a wiring harness?

You should be able to find A used one try ebay.