yamaha 50hp 3 cylinder outboard kill switch not killing

curlyoggy

Recruit
Joined
Nov 21, 2014
Messages
4
This is a repost from the yamaha engine section as i am new to this and didn't realise there was a seperate wiring section :)

Hi, i have a yamaha 50hp 3 cylinder outboard which doesn't stop when the kill cord is removed and there is no other way to stop it other than fuel deprivation. The kill button wires seem to be in place, the white wire is connected to the sealed electronic unit and the black wire is attached to a bolt, and both wires seem to be intact in the protection sleeve. The spring seems strong enough in the kill switch and the engine starts without the kill cord in place. I've also unscrewed the switch and removed the small spring that keeps the metal plate from the contacts, then made the contact whilst the engine was running to no effect. I guess the switch could be broken in some way i can't see, and i could cut the wires and then touch them together to see if the switch is the issue, however i am a little reluctant and hoped someone may have some other ideas

Thanks for your time
 

NYBo

Admiral
Joined
Oct 23, 2008
Messages
7,107
Welcome to iboats!:welcome:

Is this a tiller motor or does it have remote controls with ignition switch, throttle, etc.? Is there some other way to jumper the kill switch connections?
 

curlyoggy

Recruit
Joined
Nov 21, 2014
Messages
4
Hi, and thanks for the welcome :)

Its a tiller motor, i'm not knowlegeable enough to know if there is another way other than cutting wires to see if it's a switch problem or an enclosed wire problem - steep learning curve :)
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Disassemble what you need to in order see the back of the kill switch where the wires attach, or where they come out of the switch if they are actually molded into the switch assembly. If the two wires can be disconnected from the switch, disconnect them from the switch and then connect them together. If the engine still starts, the kill switch is NOT the problem. If the engine does not start, the kill switch is bad. If you have an volt-ohm-milliammeter you can verify the switch is bad using the resistance (ohms) setting on the meter. Connect the two meter leads to the two switch terminals or wires. If the meter shows open the switch is bad. If it shows continuity the switch is good.. If the wires cannot be separated from the switch, follow them as there is likely a connector somewhere along the way to the ignition module. Disconnect that connector and again, jumper the two wires on the ignition module side -- not the kill switch side of the connector. If the engine still starts the problem is likely in the ignition module or the ground wire is not making a good connection. If there is a connector in the kill switch harness, disconnect and reconnect that connector several times to burnish the terminals. Then try again. The problem is either the module (not likely), the wires, ground, the connector or the switch.
 

curlyoggy

Recruit
Joined
Nov 21, 2014
Messages
4
Hi Silvertip,

I've done pretty much what you suggested, figured out it could be killed joining wires under the cowling , and that it was the wires from the connector inside the cowling to the kill switch that were faulty . Unfortunately we had to cut the wires near the switch to replace the wires as the switch was sealed, hopefully they're sealed well enough now! Kill switch working great now :)

Thanks for your advice and time
 
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