QuestionQUESTION: Hi John
Murray riding mower 12.5 hp/40” cut, model 40631A, purchased 2/92. B & S engine, model 286707. I replaced the clutch safety switch because I kept having to search for the “engage point” with the clutch in order for mower to start. I could always find it and mower always started; I just got tired of searching for it. Mower(engine) is completely dead. No noises, no clicking. Battery & spark plug only 1 month old. Battery posts are clean. Assumed it wouldn’t start because the clutch needed adjusting but before I did that I jumped across the solenoid and it started OK but when I engaged the blades, the mower died. I checked the 15amp fuse under the seat and it was broken; I replaced it with a new 15, started the mower from the solenoid, engaged blades, died again. When I checked the fuse I just put in, it was broken. I checked belts and they’re all inside guides. Mower worked fine last weekend. I don’t know how to check the safety switch under the seat or on the blade engage(assuming they can be checked). I haven’t adjusted the clutch because now I’m wondering if the problem is just the fuse. Any ideas besides a short in the wires and having to trace the wiring, and if that’s the likely cause, how do you do it? I’ve never traced wiring before. Where do you start, what am I looking for, need special tools? And maybe the clutch & fuse are coincidental, not related problems. Thanks so much, Don
ANSWER: Hello Don:
>>From your Description it Sounds like a PTO Problem.
>>If the PTO has Shorted the Starter Solenoid will Not Engage as the Safety Circuit will Act as If the Blades are Engaged and If you Start the Mower the Way you have it will Also Blow the Fuse when you Engage the Blades.
>>The Following is a PTO Test File I made. Any Input is Appreciated. **If you have an Ohmmeter, Disconnect the Wiring Harness from the Front of the Clutch and Check the Resistance of the Clutch. You should have around 4 or 5 OHMs. If at or near Zero, the Coil has Shorted.**
>>If the OHM's are Correct, try Setting the Clutch Clearance.
>>The Following is a Basic File I made for Setting the PTO Clearance. Any Input is Appreciated. **Some of the Newer PTOs cannot be Adjusted.
>>If you can Get a Blade Style Feeler Gauge between the PTO Magnet and Clutch, then Set the Clearance at .015in. The Newer PTOs have the Same Set Up as the Older PTOs, except there is No Adjustments.
>>You can Also Try Turning the Spring Loaded Adjuster Nuts 1/4 Turn and Operate the Mower. Do Not Adjust Over 1/2 Turn.
>>If you have Adjusted to 1/2 Turn and the Problem is Still Present and you Know the Voltage to the PTO is Steady, then Replace the PTO.**
>>If you Hit a Snag or this Does Not Correct the Problem, I Hope to be Here if You Require More
Assistance. Hope this Helps. Let me Know What Happens, Please.
>>I Hope You and Yours are having a Happy Holiday Weekend and May the All Mighty Bless You and Yours. Be Safe and Happy. Thanks.
Good Luck
Respectfully
John
PS: I am Allowed to Answer 5 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 8pm EST (US). My New Day Starts then. Comments and Ratings are
Greatly Appreciated. Thanks.
Respectfully
John
---------- FOLLOW-UP ----------
QUESTION: Well, I don’t know if this will make it easier or harder to diagnose, but now the mower starts normally and fuse doesn’t blow, but when I engage the blades, the engine dies. All I did was adjust the clutch, change PTO switch and remove/reinstall clutch switch(it tested good continuity) and remove/reinstall solenoid, so not sure what I did right. So now my problem is just when I engage blades. I did a pretty good job of tracing the wiring, even took off the housing assembly that the steering wheel, ignition switch and blade lever sits on to check the wiring but I can’t find any broken wires. Not saying I did a thorough job but it was more than half-ass. I checked for loose connections too; found one I thought might be the solution but it wasn’t. It appears the multi-meter I have, Sperry DM-210A, only shows resistance or no resistance, I don’t think it displays ohms. But then, I had to get the guy at Home Depot to show me how to use it because the directions were useless, so I could be wrong. This is first time I’ve use multimeter. But it did show the PTO as good. Well, two of the 4 prongs tested good, the other two didn’t show resistance, whatever that means. Think it’s a broken wire touching metal somewhere or something else? Thanks so much, Don
ANSWER: Hello Again Don:
>>No Worries. This Happens all the Time in the Shop. LOL.
You can View a Breakdown of this Unit at this Site Addy; http://www.partsandservice.com/html/Murray/lt/ and Look Up your Unit. Select the Wiring File and you will be Able to View the Electrical Schematic Online.
>>Does it Happen when you Release the Clutch/Brake or Just when you Engage the Blades?
>>If Yes, then
>>the Seat Safety Switch has a Bad Connection or is Bad.
>>Are you Seating on the Seat when you are Engaging the Blades?
>>If Not, then that is causing the Problem.
>>Someone has to be Seated in the Operators Seat before Releasing the Clutch/Brake or Engaging the Blades.
>>If you Hit a Snag or this Does Not Correct the Problem, I Hope to be Here if You Require More
Assistance. Hope this Helps. Let me Know What Happens, Please.
>>I Hope You and Yours had a Happy Holiday Weekend and May the All Mighty Bless You and Yours. Be Safe and Happy. Thanks.
Good Luck
Respectfully
John
PS: I am Allowed to Answer 5 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 8pm EST (US). My New Day Starts then. Comments and Ratings are
Greatly Appreciated. Thanks.
Respectfully
John
---------- FOLLOW-UP ----------
QUESTION: Hi John
I replaced seat safety switch but engine still dies when I engage blades. I suspect this is an electrical problem but in case you ask I also checked the belt adjustment. Is OK. When I release clutch it keeps running. I am sitting in middle of seat when I engage. The new seat switch clicks when I push it in; the old switch did not, so I thought that was my problem but guess not. The switch connectors appear to be tight enough for good contact. Any ideas? How about bypassing the switch to make sure switch/connection OK? And how do I do it? I know you place a jumper wire between the contacts in the switch, but one switch-pigtail has prongs and the other pigtail doesn’t have anything to attach a wire to, just square metal holes the prongs fit into. So how do you attach a wire, or is there a better way? How about cutting off the switch with wirecutters and splicing the 4 wires together? Thanks so much.
AnswerHi Don:
>>Lets Check something else First, before we Check Any Switches.
>>Check the Charging Voltage from the Stator/Charging Coils.
>>If the Stator/Charging Coil is Not Charging Correctly, then you will have the Problem you Described.
>>For Testing the Electrical (Charging) System on Mowers you can Use this Site Addy; http://engines.myfaqcenter.com/Answer.aspx?p_faqid=3438 and Use the Link for AC Volts/DC Amps Meter Setting Chart. This is for Briggs Engines and Works Well for Kohler, Kawasaki, Tecumseh and Other Engine OEMs.
>>If you cannot Send a Follow Up, Please Start a New Question Line and Refer to this Date.
>>Thanks.
>>As Always, If you Hit a Snag or this Does Not Correct the Problem, I Hope to be Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Be Safe and Happy. Thanks.
Good Luck
Respectfully
John
PS: I am Allowed to Answer 5 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 8pm EST (US). My New Day Starts then. Comments and Ratings are Greatly Appreciated. Thanks.
Respectfully
John
