Short in Wiring Harness?

My '72 1150 started a new behavior. We can be out all day fishing, no problems but when it comes time to load the boat, the motor keeps dying.
At first I thought mixture, but the motor didn't sputter or hesitate and stop, it was exactly like turning the key off.

The next time out we experimented, turning the wheel back and forth and every time when the steering wheel was at the exact same spot, the motor quit. Move the wheel, and it starts right up.
Since the wiring harness from the boat to the motor moves when the motor turns, I figured a wire was broken or shorting out.
I have pulled the complete control box and ext. wiring harness out and placed it on my living room floor. Everything looks in very good condition. The continuity meter and I have moved the wires every which way but no luck.
For the life of me, I can not find any broken wire or short.

I can think of only 3 wires that could cause this. The red (always on), black (ground) and the white (ignition which the key turns on). While running, these are the only wires that could shut the motor off.
Any ideas?

Thanks

Re: Short in Wiring Harness?

The wire is partially or completely broken at the quick disconnect plug. To isolate which one it is, put some jumpers from the battery to the motor, to eliminate the boat wiring harness. If it still stalls, it is the white wire from the ign switch, or power to the switch. Shove a voltmeter into the tach plug. You will read +12VDC when the ign switch ison. Turn the wheel and see if you lose it. if so, it is the red to the ign switch.

Re: Short in Wiring Harness?

+1 to what Chris said. My '76 1500 was doing about the same thing. This boat is new to me. The 12V from the ignition switch wehn key is on is where my problem was. I could wiggle the harness where it plugs into the motor and the voltage would be all over the place. I tore my engine harness apart & left the wires on the pins and plugged them in individually, taped everything up good. Everything tests good now with a meter.
If everything goes okay (gonna water test it this weekend) I'll buy a new engine harness.
CDI makes the harnesses, boat side and engine side, and prices vary quite a bit. boatfix.com has the engine harness for $99 which is cheaper than anywhere I have found. Good Luck.


Part #'s for my motor which I think would be the same for your are

414-2770 for the engine harness
474-9550 for the boat harness

these are the CDI aftermarket universal harnesses.

Re: Short in Wiring Harness?

Chris1956,
Thanks for the testing tips. I have just been running a continuity meter between the back of the ignition switch to the holes in the "quick connect" and bending the wiring to simulate when the motor turns. With your easier method, at least I should be able to pin point the bad wire.
That's 90% of the battle. Replacing the wire is the easy part.
Sounds like you agree that this problem could only be caused by the white or red wires. I think a short in the black might do the same. Since the black is the only ground between the motor and the boat, a break in the gound might cause the motor to die.
At least now I have an easier way to test.

Thanks

ALLABOARD,
The interior wiring harness, 18-2770 is fairly new at about 2 months old. Your experience sounds similar. I am going to check the pins at the "quick connect".
I have a feeling the short or broken wire is somewhere in the exterior harness and/or "quick connect plug". That is the ONLY part that moves when the engine swivels.
Since the 474-9550 runs about $200, I'm hoping to find the broken wire and replace it for $0.64 (14 ga. wire) a foot from WestMarine.
Thanks, at least I have your ideas to test this further.

P.S. Sierra also makes the boat harness #18-5511.

Thanks for the ideas.
Thanks