Motor runs great, but wont shut off.

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Greedy1

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Joined
Jan 7, 2013
Messages
4
I have a 93, 75hp Mariner outboard motor that runs great, but it will not shut off. I do not see any loose wires. Thoughts are that the ignition system needs to be opened or grounded. But not sure which one. Opened---Power removed from circuit. Grounded---like it sounds.

Thanks

Greedy
 
M

Maxz695

Guest
Re: Motor runs great, but wont shut off.

the black yellow wire I believe on the switchbox is the kill wire from the key switch and the tilt kill switch. Ground that and it should shut down the engine. If you have to choke the engine to kill it for now until you find the reason. See picture for the correct kill wire View attachment 178390 This is a 70 HP though. Sounds like the key switch is not grounding or the ground wire broke from it
 
G

Greedy1

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Jan 7, 2013
Messages
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Re: Motor runs great, but wont shut off.

Thank you for the picture, it will help a lot. I replaced the key switch as I thought that that might be the problem. No change. I will get some heat in the barn and try tracing down the wires some more. Day time, weekend forcast is above freezing, so I can get out the water hose.

Thanks

Greedy
 
M

Maxz695

Guest
Re: Motor runs great, but wont shut off.

you should be able to ground that wire on the switchbox to get it to shut off I think you may want to unplug the pigtail at the engine harness and spray some Pb blaster in the connectors as they sometimes build up corrosion and don,t make a connection. The pigtail might be located in this area in the picture View attachment 178392
 
Silvertip

Silvertip

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Sep 22, 2003
Messages
28,762
Re: Motor runs great, but wont shut off.

Does the engine die if you pull the kill switch lanyard?
 
G

Greedy1

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Jan 7, 2013
Messages
4
Re: Motor runs great, but wont shut off.

Nope, the motor starts and runs fine with the safety kill switch pulled. That switch acts like it is not even there. I disconnected it completely, and then directly wired the two switch leads together. No difference at all.

Thanks

Greedy
 
O

oldman570

Lieutenant Commander
Joined
Mar 25, 2011
Messages
1,615
Re: Motor runs great, but wont shut off.

Is the boat equipted with gauges, and if so do they work? If the gauges work then the ground from the motor to the control is bad or cut in the control. JMO
Oldman570
 
G

Greedy1

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Jan 7, 2013
Messages
4
Re: Motor runs great, but wont shut off.

Yes the boat has gauges and they all work fine. I will work on the wiring some more as soon as the weather permits. It gets pretty cold in the barn. Seems like I will end up pulling a new wire.

Thanks

Greedy
 
quicktach

quicktach

Petty Officer 1st Class
Joined
Aug 24, 2012
Messages
394
Re: Motor runs great, but wont shut off.

Get a wiring diagram if you don't have one. Get a good VOM or multimeter (one with a continuity buzzer is handy) and start testing for continuity. You aren't grounding out the engine to kill it. Broken wire, dirty/painted ground. Defective contacts in kill circuit ? Is the CDI grounded OK?
 
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