Murray Riding Mower-Engine Cutoff When Clutch Released

kenh99September 6, 2010

Hi All, Sure hope ya'll can help!

Have a Murray Select Riding Mower, model # 40507x8A, 12.5 hp B&S. Purchased it new in 2002 (I think).

Primary problem: Engine cuts off when clutch/brake is released.

Background: Not long ago the seat safety switch broke so I eliminated the switch and connected the 2 yellow wires from the switch together to complete the circuit. Everything worked fine. Yes, I know it defeats a safety feature but I'm a safety conscious guy so...

Now, a week later, the engine started cuting off when the clutch/brake is released after starting.

I've checked the ground wire for that seat safety circuit (under seat area), cleaned it and reattached. Still no go. The 2 wires from the former safety switch/button are well connected, clean and taped securely.

Any suggestions for toubleshooting or repair are sincerely appreciated!!

Thank You!


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Connecting those 2 wires together the mower should have
not started at all, so you need to take out, disconnect
those wires altogether, your problem should be in that area.


    Bookmark   September 6, 2010 at 4:16PM
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Thanks Fish,

I assumed that the safety switch completed the circuit when the plunger is depressed by sitting on the seat. Was I wrong and when depressed it opens the circuit?


    Bookmark   September 6, 2010 at 7:54PM
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Seat switch is open when seat is occupied.
Seat switch closes when seat is vacant.
Closing the seat switch connects the magneto kill wire to ground, stopping the spark production and causing the engine to quit running.
The clutch switch is part of the interlock circuit and WILL permit the engine to run with the seat empty provided the clutch/brake pedal is down.
But since you connected the seat switch wires together, the clutch switch is the last switch to close and now it acts as though the seat is empty, even when the seat is actually occupied.

    Bookmark   September 7, 2010 at 12:46AM
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Thank You Mownie for that explanation!!

Will disconnect the wires tonight when I get home and give it a try.

Take Care,


    Bookmark   September 7, 2010 at 9:41AM
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I wish I had said it....

    Bookmark   September 7, 2010 at 10:05PM
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