bford1

I had an odd thing happen last weekend. I turned off the port motor and noticed it was still running. When I shut off the starboard motor it then shut off. Tried it the other way around and the starboard won't shut off without also shutting off the port motor.

Both start normally except that it used to be that when I would turn on each key the warning alarm would beep twice. Now it only beeps when I turn on one key and not the other. It's like a wire got crossed or soemthing. But, I have done no work under the dash or anywhere around the ignition.

Anyone else ever experience this? It's not really causing a problem (at least not yet).

Boat is a 2002 Formula 400 SS with twin 500 EFIs

Thanks in advance.


Brent

Outdrive1

Do you have a single kill switch?

bford1

Do you meant the kill switch on the lanyards you would attach to your wrist? I do have two of those lanyards.

stevesxm

well... what could really do this ? somehow the ignition switch is being backfed when the other motor is running... which says alternator diodes or something... or as if a dual battery switch had done something bizzare...

the first question want to ask is if you have added anything electrical to the system since the last time you noticed it worked ok.

the last time this happened to me was on a ford pickup truck with a bad light switch. started it up and from that monent on couldn't shut it off. switch was backfeeding the ignition. what else runs off that ignition switch ?

glassdave

iTrader: (1)

bad grounds can cause some funny things as well. But yea it is being back fed from somewhere.

bford1

First, thanks very much for your input.

I don't have a dual battery switch. It has one switch for each battery and one switch (plastic keys actually) for the parallel switch. Parallel is turned off.

I have not added anything to the electrical system or made any changes at all. It was working normally at the beginning of the weekend. I have been having trouble with water in one of the gas tanks so I had to start and stop one of the motors repeatedly as I was dumping the fuel out of the water separating fuel filter. So, I started and stopped one engine about 20 times. Then all of the sudden that engine wouldn't stop without the other key also being off. I thought I had worn out the key or the ignition switch at first. But, the other engine won't shut off either unelss both keys are off. Both engines start normally. Could it be a short between the two ignition switches behind the dash?

I have no idea how to troubleshoot this. I guess the big question for me is this something you would worry about? I would normally be shutting off both motors at the same time anyway.

Griff

The first thing to do is look behind the dash at the wiring for the ignition/key switches.

I would make sure to get it fixed. It will most likely get worse or burn a wire.

Thunderstruck

The dash instruments and ignition is powered when the key is turned on. Usually that is a purple wire that is powered from the ignition key. Also, the power probably comes up to the keys with a yellow wire with a red stripe.

I would say that the purple ignition wire for the port motor and starboard motor are touching somewhere, probably in the dash. Turn on the stbd key and check the purple wire on the port motor with a volt meter (under the dash somewhere) and vice versa. (Or look at the port gauges when the stbd key is turned on.) That will verify that the purple wires are touching somewhere. Then it is a matter of checking gauge by gauge, wire by wire under the dash until you find it.

I would look at the ignition switches first. Starting and stopping, working the key back and forth might have twisted one of the switches and caused the purple wires to touch.

I think that if the yellow wire w/ a red stripe, the power wire that has continuous 12 volts were touching somewhere the motor would not shut off with either key so I would not bother too much with that wire. Also, if the ignition were somehow powered up from a power source in the engine compartment you would not be able to shut off the motor with any key.

Try looking at the purple wires under the dash on the back side of the ignition keys.

Fun problem.

MOBILEMERCMAN

Do you have a trim override? Depending on where the switch gets its power it could be part of the problem. The trim generally uses power from the trim motor and is protected by its own fuse or breaker. It is possible that if the power is taken from ignition purple to operate switch that a cross could occur. I doubt you have a syncro gauge, but it would also be a thing to check.

Others are correct, fun problem, likely to get worse, and may burn wires. Start at key switches trace purple wires, be systematic and thorough.

Good luck.

Westcoast

Check the parallel switch. Even though it is off it could have shorted and be feeding power to the other side.