# Murrary Riding Lawnmower Won't Start



## Bushman (Mar 28, 2010)

I would try a new battery. Sounds like yours is dry and won't hold a charge. Double check all cables and grounds make sure they are clean and free of corrosion.


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## Yoyizit (Jul 11, 2008)

lerxstrulz said:


> I'm getting a clicking sound when trying to start.


I'm surprised that replacing all that didn't fix the problem. Perhaps you are making some basic, false assumptions.

Post a legible schematic and borrow a VOM or a 12v test [incand] lamp. 

The cranking circuit is simple so there are not that many points to check with a symptom like this.


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## Giles (Jan 25, 2010)

A lot of money and anger is associated with batteries. 
In most cases, the best way to identify a bad battery is to use jumper cables connected to a known good car battery. I say--"in most cases"-- because a dead shorted battery will not yield good results. 
Just last week, a friend of mine called me for help on a small tractor he just bought. He had replaced the almost new battery with a new one, changed the startor selenoid, then changed the starter, and continued to check out wireing system.
He had bought the tractor knowing it had this problem.
The first thing I did was to jump the tractor off with his truck and it fired right up.
Two new batteries were bad.
Both batteries were, you gessed it, Made in China!:thumbdown:
This may not be your problem but it is easy to check.


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## Yoyizit (Jul 11, 2008)

*On second thought*

On second thought. . .

The current drawn from the battery while attempting to crank the engine is a good indicator of what is going on.

You can measure this with a clamp-on DC ammeter, or, with a DVM and knowing the length and wire gauge of the heavy wires that carry cranking current, you can use this wire as a shunt. 
I'd expect less than 1/4th volt across the length of this wire while drawing normal cranking current. There'll be about 30 mVdc across one foot of #8 copper wire @ 50A. Pierce the cable insulation with safety pins to make your millivolt measurement.

This test should also indicate if the engine is seized. Locked rotor current for a car starter motor is about 400A [@4v across the motor] so this should be much less.

What is the Amp-Hour rating of the battery?


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## bob22 (May 28, 2008)

lerxstrulz,
How old is the mower? Have you tried jumping it with a car to see if it is a power issue?


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## lerxstrulz (Apr 10, 2010)

Hi guys and thanks for all the replies. I was able to go take another look at it today and here's were we are (getting closer!)

I hooked it up to the car and it cranks continuously but won't fire, so I know I'll have to replace the battery. I pulled the armature and cleaned it and reset it but still no good. I pulled and cleaned the spark plug and still no good. I cranked it while the plug was out and gas is getting to the plug just fine so it's not a fuel line issue.

However I did notice that there was no "spark" in the plug when I cranked it, so I replaced the spark plug and still no go. So I'm thinking it's the armature (again dadgummit I replaced it just last year....)

What do you think?


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## Yoyizit (Jul 11, 2008)

lerxstrulz said:


> there was no "spark" in the plug when I cranked it


You may need a new ignition coil, in addition to the cranking problems. 
When you test for the spark, don't have it jump more than the gap on these small engine spark testers. Larger gaps overstress the coil insulation.


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## lerxstrulz (Apr 10, 2010)

On closer inspection of the coil wire leading to the plug its got a spot that's thicker and the paint (printed numbers) on the insulation are a little messed up so I'm leaning towards a spent coil. I'll order a new one and let you guys know if that was it.


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## Rhizzlebop (Jan 28, 2009)

Did you leave gas in it over the winter?

I usually do as well (though I shouldn't) but my stuff usually works fine.

However, this weekend, I pulled out the pressure washer (a 5HP Honda / Troy Built). It wouldn't even attempt to fire.
I choked it, I checked the spark plug all were fine. I pulled and pulled and pulled some more and it wouldn't even puff smoke like it wanted to light a spark in there AT ALL.
I checked the gas, and it had a 1/3 tank.

Finally, I said what the heck, let me fill it with fuel, (2/3 good fresh fuel).

It fired within 3 pulls!!


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## lerxstrulz (Apr 10, 2010)

Rhizzlebop said:


> Finally, I said what the heck, let me fill it with fuel, (2/3 good fresh fuel).
> 
> It fired within 3 pulls!!


Yep first thing


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## lerxstrulz (Apr 10, 2010)

Well...still not working. I replaced the ignition coil and the result is the same. It will sit there and crank but just will not fire.

On a hunch I disconnected the safety switch under the seat and it does the same things....cranks but no fire. So now I'm thinking there is something in the safety system preventing it from firing? Next thing is to pull a schematic and trace the electrical system for the ignition. I unplugged the under-seat safety switch from the harness and jumped it with a heavy copper wire but same result. I did notice there are 3 wires coming off that harness: 1 to the battery positive and 1 to ground and then another just hanging there. I thought maybe it was disconnected from something but I can find another wire that's not connected 

I'm going to pull a schematic and see if I can figure it out but if anyone has any ideas I would appreciate them.

Thanks!


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## lerxstrulz (Apr 10, 2010)

Hi Everyone,

Just wanted to let you know I FINALLY got the mower working yesterday. I traced the "safety" electrical system and bypassed the clutch switch and it works, but unfortunately that also bypasses the seat safety switch. 

Anyway, I'm giving the entire thing a good clean out and making sure to take apart and clean all of the electrical connections really well, but it sure was nice to be able to mow my yard with the tractor for the first time in nearly a year 

Thanks again for all of your help!


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## downunder (Jun 13, 2008)

I'm glad you finally got the mower going!

To constructively critique:


> Perhaps you are making some basic, false assumptions.


Yoyizit makes a very good point. That was a lot of work and expense you went through to find something this (sort of) basic. But then, that's why I would rather work on almost anything than troubleshooting electricals.


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## lerxstrulz (Apr 10, 2010)

downunder said:


> I'm glad you finally got the mower going!
> 
> To constructively critique:
> 
> Yoyizit makes a very good point. That was a lot of work and expense you went through to find something this (sort of) basic. But then, that's why I would rather work on almost anything than troubleshooting electricals.


That's ok for me, because now I REALLY understand how this thing is put together. The solenoid and ignition/key were from a couple of years ago, and this time I only replaced the spark plug and ignition coil (less than $40 total.) I don't know how long a coil is supposed to last, but it's got a new one now  A repair shop said it would be at least $300 to get in there and figure it out, so I figured if I spend $50 or so and can't fix it then I'll determine if it's worth it to get it fixed or sell it for parts. The timeframe was more of being lazy then anything else, I still had working push mower and although it took significantly more time to mow the yard, it was good exercise


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