Murray Riding Mower Won't Shut-off

bblanton

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I should have gone back to bed this morning. I purchased an used Murray 17.5 HP with a 42" deck for my wife to help me. We have mowed with it for three times with no problem.

This morning, my wife wanted to mow. I tried to start the mower but could not get the key into the slot. We tried and tried. I finally removed a front panel and removed the old ignition switch. It has seven connectors. I called a mower repair. All they asked me was how many connectors did my switch have. They had one but they are 25 miles away. I called the local Tractor Supply Company. The girl that answered found a seven connector in stock.

I got it and installed it when I got home. As I was trying to put it back in the dashboard, I found a loose black wire. I saw a place in the plastic portion of the old connector without a wire. Being very hot and sweaty, I connected the black wire in the connector. I tried to start it up. The mower would almost start. Then it did. I chalked it up to a battery that will have to be replaced next Spring.

I turned the key to turn off the mower. It kept running. I got off the dead man's seat. It kept running. I removed the negative ground to the battery. It kept running. I removed the ignition switch and pulled the connector. It kept running.

I saw the wires going into the ignition switch were yellow. I had connected a black wire to the plastic connector and a yellow wire to the ignition switch. I reversed the wires and reconnected the ignition switch. I turned the key. It kept running. I removed the positive lead to the battery. You know what happened.

I decided to mow and run the gas out. I finished the mowing with a fourth of a tank left. I was going to let the gas run out but I could not let better enough alone. I had thought about pulling the boot off of the spark plug early in this process but that area was very hot. I thought I would give this another shot. I gently wiggled the boot without burning my fingers. I kept working at it until the park plug wire came out of the boot. IT QUIT RUNNING!

I know that I am stupid to pull the spark plug wire out but my question is, "Did I do something to the switch which prevented it from shutting off?" I may have mixed-up the yellow and black wires when putting the connector of the ignition switch. I need to fix this myself if possible.

,
 

Rivets

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Sounds to me like they gave you the wrong info and switch. There are about a dozen different seven terminal switches. Take your old switch and your new one and look at the markings on either the terminal or plastic. They have letters with have to be in the same location.
 

bblanton

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Sounds to me like they gave you the wrong info and switch. There are about a dozen different seven terminal switches. Take your old switch and your new one and look at the markings on either the terminal or plastic. They have letters with have to be in the same location.

Thanks for the quick reply. I will take the old one by the repair shop on Monday.

Do you have any idea why it did not shut off when I removed the new ignition switch?
 

Rivets

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By not having the correct switch, when you plugged the wiring harness in the kill circuit was not plugged into the right terminal, is my guess.
 

hjk

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I have the same problem. I switched engines on my murray from a 14.5 hp briggs to a 15.5 hp briggs and the key switch that shut the original engine off will not shut the 15.5 briggs off now? I replaced the switch with a oem briggs switch and still will not stop the engine?
 

Rivets

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Look at the back of the two switches. Then look at the new plug. Are the wires going to the correct terminals. The terminal that shuts out the engine is M and must be connected to the magneto kill wire.
 

jtxl

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I have an old murray 16.5hp riding mower. Last spring I replaced the ignition with a new one. Today when I was finished cutting, the mower would not shut off. I even took the key out and it still ran. I had to pull the boots off both spark plugs for it to stop. What could be going wrong?
 

reynoldston

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Rivets is right. It sure sounds like you got the wrong switch.. To turn the mower off you need negative to the primary coil terminal. The switches I have seen on ALL mower have a plastic plug that plugs right into the ignition switch. So why would be the reason of taking the wires out of this plug and start switching wires around? Sounds like a good way to do damage like burn your coil up.
 

bertsmobile1

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The shut off works by connecting the coil trigger wire to earth.
On all switches made for about the last 20 years this means connecting the M ( Magneto ) wire to the G ( Ground or earth or - ) wire.
On some plugs the G wire is part of the plug while others have a single separate ground wire ( don't ask me why ).
The M wire goes from the ignition switch to the ignition coils and usually had a round plug hiding behind the starter mower.
So if your engine does not stop it is because either the switch is not connecting M with G or the M wire is dissconnected / broken somewhere.
 
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