Twin engines will crank but not start unless both ignition switches in the on position

fishlips

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Just had a cobia tower installed on my 2005 282 Sailfish with twin 250 4-stroke outboards. Tower has steering wheel, control binn twin, and a deadman switch. There's no key switch in the tower only a deadman switch. Since the outboards are 2005 Yamaha's (800 hrs) had to use mechanical vs digital controls to the tower station. Yamaha dual station selector unit, with 2 dual station unit - throttle and 2 dual station unit - shift installed. All this work done by an authorized Yamaha dealer / shop at the marina. Post-modification, the engines would crank but not start. Only if both main helm station ignition switches were placed in on position would either engine crank over. After conferring with Yamaha techs, they ordered a replacement key switch panel assembly for the main (original) helm station - some concern that a diode may have blown during tie-in of the new deadman switch or the diode just coincidently failed (old age). No different results after replacing key switch panel. Disconnected the tower deadman switch from the ignition ckt and still no change...either engine only will start if both engine key switches are in on position. Marina techs and Yamaha techs apparently stumped. Trying to tell me that this might be an unfixable issue and attempting to review wiring diagrams and Yamaha tech bulletins to tell me why it's that way. I don't want to have to deal with this workaround, but more importantly don't like the idea of what happens if I were to have one engine failure while out on the water...particularly if an electrical problem and I don't want to have to leave the problem engine's ignition on to be able to run back to the dock on the good engine. Any help or suggestions would be much appreciated.
 

fishlips

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Realize in my original post I said that only "if both main helm station ignition switches were placed in on position would either engine crank over." I meant to say "would either engine start. When you attempt to start them one at a time with the keyswitch on the motor you're not starting in the off position - the engine you are attempting to start will crank, the horn continues to sound, but it will not start. Same for both engines when you try to start one at a time as you would normally.
 

Halfhitch

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I am surprised that your dealer has come up short on this. To my way of thinking, if you don't have a start feature upstairs then all you need is a kill switch wired in parallel with the ones at the key switches. That one lanyard-pull kill switch will kill both engines and is your deadman switch(if you wear it).The binacal neutral switch upstairs will have to be wired into the circuit also. If if you do those two things, you should be able to get rid of all that dual-station selector switch business for the starting circuits and go back to your original start switches that worked.
 

fishlips

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The new selector switch at the main helm station is a mechanical device that selects what binnacle (main or tower) is controlling throttle / shift on the engines. My understanding from what I've been told is that the neutral switch is on the engines and whatever control station is selected by the mechanical selector switch in turn controls the neutral switch on the engines.
 

Halfhitch

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There's a lot about that system that I am not familiar with especially from afar like this. It is an intriguing problem though. I wish I could be of some help but it's over my pay grade a bit I'm afraid. When you finally work through it though and figure out the snag in the system, please get back to us and let us know what it was.
 

wspitler

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I believe the neutral switch, in any position other than neutral, will not allow the engine to crank at all. If it cranks, but the ECM/ignition is grounded out, the engine will crank but will not start. Seems the problem is that the ignition or kill switch wiring is in series rather than parallel. Both ignition switches must be on to provide power to the ECM/ignition. Probably a installation error. With both engines running, if you turn off one ignition, do they both shut down? Power to the ECM/ignition system is most likely the issue.
 

fishlips

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I see on the rigging schematic that several of the 'common' components have different part numbers for the main station and the remote station. Perhaps the wrong parts were installed.
My outboards are 2005 vintage. Mechanical shift/throttle not digital. So to get second station controls for tower, installed a mechanical main/remote station switch and 4 switch / mechanisms (1 throttle/1 shift for each outboard). The only electrical tie-in to the starting ckt is the second deadman switch.
 

seasick

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Sorry, I missed the mechanical aspect of the control. Just to be sure I understand; when you have this issue, the emergency cutoff (kill) switch has the lanyard clip in place. Is that correct? If so, when the motor or motors are running, confirm that pulling either kill clip , main or remote, , shuts down the motors.