Short in Ignition Wiring

[nfisherman]

Hello, I have a 2000 Yamaha F115 TLRY outboard. There's an intermittent problem with my ignition. Sometimes it cranks forever but won't start. Other times it starts up and runs great. When it doesn't start, I can wiggle the wiring harness of 3 or 4 wires just before they enter the engine and it starts and runs. The last time this happened, the engine would not shut off when I turned the key off. I wiggled the harness and the engine went off. I plan to cut the outer insulation off of the harness and inspect the inner wires. I think there's a short or a broken wire in there. Can anyone think of anything I should be looking for? Thanks.

 

[mjf55]

Hello nfishernam, welcome to iBoats. Which set of wires are you moving? Can you describe where it is? Can you trace where they go on the engine? A picture would be better, but you cannot do that until after 3 posts.

EDIT: If you do slice open the outer insulation, post the wire colors so we can help more. I am currently looking for a wiring diagram, but not finding a good one yet

 

[Silvertip]

Shorts blow fuses so that's not the issue. Intermittent connections cause what you are experiencing.

 

[gm280]

Before cutting into the wiring harness, see where each wire goes to at the engine side and make certain those connections are clean and shiny metal. Could be you have a loose connection and nothing more. Unless you see damage to the wiring harness, like a cut or broken insulation or such, it is rare for wires to break in the insulation for no reason. JMHO!

 

[nfisherman]

Thanks for the replies. I have inspected the connections but I can't see anything wrong. I've taken it to two professional marine mechanics. One couldn't find a problem because it didn't occur when he had it. The other replaced the ignition switch, but that didn't fix the intermittent issue. I store my boat a a few miles from my house. I can get back to it this weekend and inspect the wiring and post pictures then. There's a bundle of 3 or 4 wires that enter at the front of the engine. These are the only electrical wires that enter there besides the battery cables. The other things that enter there are the fuel line and shift cables. I don't recall the colors of the wires at the moment. I will follow up this weekend with either how I fixed it or pictures and more questions. Thanks very much.

 

[nfisherman]

I fixed it. The yellow and white wires were broken in the main wiring harness where it enters the grommet at the front of the engine. The breaks were inside the insulation. I pulled on each wire, but on these two, the insulation stretched and broke. I spliced the wires together and the engine started and stopped perfectly. This is only a temporary repair. I will replace the harness now that I've found the problem. Sorry, I'm not able to upload pics yet.

 

[gm280]

I fixed it. The yellow and white wires were broken in the main wiring harness where it enters the grommet at the front of the engine. The breaks were inside the insulation. I pulled on each wire, but on these two, the insulation stretched and broke. I spliced the wires together and the engine started and stopped perfectly. This is only a temporary repair. I will replace the harness now that I've found the problem. Sorry, I'm not able to upload pics yet.

Well that is certainly great news. Was the break at a bent area of the harness? Just wondering what could have contributed to that.

 

[nfisherman]

Yes. I think it was just fatigue from tilting the motor over time. The breaks were just in front of the grommet where the harness enters the engine. I could start the engine, or not, depending on how I squeezed this area of the harness. There was no visible damage to the harness casing or the insulation on any of the wires inside. I'm going to buy a new harness and hope it lasts 16 years like this one did. ;-)

 

[nfisherman]

No Title

I'm happy to have found and fixed the problem, if only temporarily. I bought a new 10- pin main harness yesterday. It appears to be the correct part, but the dealer that originally rigged the boat cut the "side" plug off of the helm end of the main harness and connected the wires with bullets connectors. The wire colors on the old and new harness don't exactly match and the new harness has a black wire that isn't on the old harness. I presume the black wire is just a ground that can be cut and taped. The plug on the right in the attached pic is the one that I need to cut off. The wire colors on it are black, red, brown (2), blue and pale green. Can someone tell what these colors are for? I want to make the correct connections without frying anything. Thanks.

 

[nfisherman]

I have the ground, trim up/down wires, 12v + wires figured out on the harness. I'm left with two brown wires that go to the side plug. One wire is slightly more brown and the other is a little more orange but still brown. On the old harness, two brown wires connect to a 2-wire bundle, but I don't know where they go. I'm guessing they're for the ignition/neutral safety switch, but I don't know. Can anyone identify the two brown wires? I've looked up wire colors for the main harness, but I can only find colors for the main plug.