Need Help with troubleshooting ignition switch on Murray 12.5 HP

Rivets

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  • / Need Help with troubleshooting ignition switch on Murray 12.5 HP
Ok, that should be good, Let's do a couple of more. B terminal to L terminal. Off position no continuity, run position continuity. S terminal to L terminal. Off position no continuity, run position no continuity. M terminal to G terminal, run position no continuity, off position continuity.
 

Rivets

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  • / Need Help with troubleshooting ignition switch on Murray 12.5 HP
Also, please check to see if you have continuity between the L and X terminals both in the run and off positions. I am trying to find out why the schematic drawing is not consistent with the way you say the key switch is wired. FYI, Going to be in and out all day so I don't know when I'll be checking in.
 

MTD

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  • / Need Help with troubleshooting ignition switch on Murray 12.5 HP
Ok, that should be good, Let's do a couple of more. B terminal to L terminal. Off position no continuity, run position continuity. S terminal to L terminal. Off position no continuity, run position no continuity. M terminal to G terminal, run position no continuity, off position continuity.

NEW SWITCH

B to L: OFF gives No Continuity, RUN gives No Continuity

S to L: OFF gives No Continuity, RUN gives No Continuity

M to G: OFF gives Continuity, RUN gives No Continuity



ORIGINAL SWITCH


B to L: OFF gives No Continuity, RUN gives No Continuity

S to L: OFF gives No Continuity, RUN gives No Continuity

M to G: OFF gives Continuity, RUN gives No Continuity
 

MTD

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  • / Need Help with troubleshooting ignition switch on Murray 12.5 HP
Also, please check to see if you have continuity between the L and X terminals both in the run and off positions. I am trying to find out why the schematic drawing is not consistent with the way you say the key switch is wired. FYI, Going to be in and out all day so I don't know when I'll be checking in.



NEW SWITCH


L to X: OFF: No Continuity, RUN: No Continuity

*** I know you didn't ask for this but L to X gives Continuity in the LIGHTS position. The positions of this switch are: OFF, LIGHTS, RUN, START



ORIGINAL SWITCH:

L to X: OFF: No Continuity, RUN: No Continuity

LIGHTS: Continuity




I'm not seeing what is different between the drawing and the way the switch is wired. The wire colors match exactly.
 

Rivets

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  • / Need Help with troubleshooting ignition switch on Murray 12.5 HP
Something's not right. In post #59 you said top right you had orange wires and bottom left you had red wires. In post #62 you show top right as battery terminal and bottom left as solenoid terminal. In the schematic red wires should go to battery terminal and orange wires should be connected to the solenoid terminal. Do you see the difference I am seeing? As I see it the engine will only turn over with the deck down and foot off the brake petal.
 

MTD

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  • / Need Help with troubleshooting ignition switch on Murray 12.5 HP
Something's not right. In post #59 you said top right you had orange wires and bottom left you had red wires. In post #62 you show top right as battery terminal and bottom left as solenoid terminal. In the schematic red wires should go to battery terminal and orange wires should be connected to the solenoid terminal. Do you see the difference I am seeing? As I see it the engine will only turn over with the deck down and foot off the brake petal.


Ok, I think what you are seeing is the difference between the two switches - the original switch & the new switch (which I have not used). What I said is correct, the original switch has B (red wire from battery) at bottom left and S (org wire from solenoid) at top right. The NEW switch has the B and S in reverse positions (as well as the L & X).

Stated another way, if you look at the factory schematic, the original switch in my mower matches the schematic exactly - red wire goes to bottom left & org wire goes to top right. (white wire goes to top left & vio wire goes to bottom right).

I had thought the same thing you did - that the schematic made it look like the mower would only start with deck down. What I know for sure is that the original switch is wired as I stated above and before it broke the mower only started with the deck UP.

**As to the difference between the two switches, the only thing I can think of is that the switch for the B and S is a simple single throw type and only requires an ON/OFF connection, meaning that it apparently doesn't matter whether B or S is top right or bottom left so long as they are limited to those two positions. Either that or the NEW switch simply isn't compatible with my mower. That's why I never tried putting the new switch in. But since the original switch was tested out of circuit and tests good it shouldn't be an issue.
 

Rivets

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  • / Need Help with troubleshooting ignition switch on Murray 12.5 HP
I understand what you are saying, but all the tests I asked you to do have come back with the same results for both switches. That is the problem for me. When testing electrical circuits you can NEVER ASSUME ANYTHING. I still believe the two switches are the same. There are many different types of six terminal switches, some know as simple ( meaning connecting two terminals at a time ) and others known as complex ( means multiple terminal connections ). I am trying to find out what type you have by the picture and what you tell me. I am going to be unavailable until later this evening. You might try to install the old switch back in and go the the electrical procedure I posted earlier and see what happens.
 

EngineMan

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  • / Need Help with troubleshooting ignition switch on Murray 12.5 HP
Any new's, update's on this one...?
 

MTD

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  • / Need Help with troubleshooting ignition switch on Murray 12.5 HP
I installed a new PTO safety switch and harness assembly. Everything now reads as it should and, finally the mower cranks again!

Best I could tell, someone had previously either tried to fix the problem with auxiliary wiring or had attempted to bypass the safety switches.

Thanks again to everyone for their help & support ! :thumbsup:
 

EngineMan

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  • / Need Help with troubleshooting ignition switch on Murray 12.5 HP
Well done to you, you made it...:thumbsup: hope now you have many happy hours mover....:smile:

Its been a long road, but you got there.
 
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