Hi guys..

I have a Yamaha 4-stroke OB T60TLRC controlled with 704 set up- 2003 was the year of manufacture, I think. Trouble began last year when the engine would not shut off. I took care of it by disconnecting the fuel line. When the engine did stop for lack of fuel, I could start it up again fine.
Before I had a chance to troubleshoot that problem, the engine would not turn over. This was in the fall, and I had a mechanic come out to look at it. He couldn't figure out the problem, but did jump-start the engine so I could get the boat off the water and put it in winter storage.
Now I am dealing with it. Battery is fine. All of the auxiliery curcuits work fine. The tilt-trim works. The three fuses off the positive battery terminal are fine. Those fuses that I found in the engine itself are good- though I didn't muck around much.
Taking a flyer, I spent a hundred bucks on a new ignition assembly- but with the same results. Interestingly, when I disconnected the old assembly, the three wires that connect independently to the main wiring had clear plastic protectors that were singed- full of carbonacious deposits- as if they had been overheated.
So that's where I stand. Before I go out and start tracing things back, hopefully someone on this board can steer me to an easy solution.
Thanks in advance!

The main 10 pin harness(engine to key switch) may have a broken wire inside it. Could be a bad neutral safety switch in control box.

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Boats.net
Yamaha Outboard Parts

Hi, Look at the ten pin connector, look for any signs of corosion. When a outboard will not shut down, that is the first thing that I look for. The single pin connectors that are covered with clear plastic that look a little cooked, cut them out, and re do them. They probably cooked because of a bad connection. It does not matter the reason. cooked connections need to be replaced, they are a problem, waiting to happen at the most inoppertune time. Also look at the ground, black battery connector, make sure it, as well as all other battery connections are clean and tight.
I hopes this helps, Let us know how you make out. Dennis

Well, got all my stuff together- wiring diagrams and voltmeter, and went back to the Yamaha. As per advice, I disconnected the ten pin connector at the engine and had a look-see. Everything looked fine. I hooked the power up to the boat, connected all the wires from the ignition control module, and turned the key off.
As expected, no power at the ten pin.
Then I turned the power on at the switch, and checked the ten-pin connector.
Still no power.
Hmm.
So I took a better look high up in the underside of the boat that is mostly hidden by the aluminun transom.
Found the problem.
Squirrels or rats had apparently eaten through all of the lower-gauge wires that went to the motor- twelve in all.
I am glad that is the problem rather than some expensive peice of equipment that is now out of warrenty. I only hope that no permanent damage was done as the engine slowly lost control power.
I had stored the boat since new at my cousin's shed- he has a boat storage business. Previously, he made sure that we knew that his place had no rodents, and if there were any they usually come in from other boats. I wondered why he made that point to me so strongly when I never asked.
He's got rodents. Other people probably have complained about it.
Thanks for everyone's input and concern.

Sounds like you r key switch is bad!

What is the "R key switch"