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Lawn Tractor Problem


khougi's Avatar
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10-17-02, 01:22 PM   #1  
khougi
murray lawntractor engine won't turn

HI, I have a murray lawn tractor model 42572x8A that is a little over a year old and has had no engine problems before. Yesterday I started it and rode out to a spot to start useing it to pull stuff out of bushes and turned it off to get off and attache the items to pull. Got back on, turned the key and only got a hum like it was siezed up or jammed. I tried to jump it with the car and it still just kind of hummed and nothing worked. I took the top cover off the engine and could turn the cooling fan with my hands and such so I don't think the engine siezed or such. The starter jumps up into position with the gear wheel for starting but thats as far as it goes. Could the started have gone weak or could I have another problem. I bought a new battery today and had no luck. I'm umemployed telecom worker so I really need to be able to fix it myself.
Thank you for any help or info you can give.
Tim

 
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10-17-02, 07:08 PM   #2  
Hello khougi!

What brand, HP, and model# engine is on your equipment? I bet it is an overhead valve engine. If so, the valves are probably in need of adjustment. It could be other problems as well, but this is the most common and was the first thing that hit me. Post back the needed info so we can give you more detailed info.


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10-18-02, 08:27 AM   #3  
khougi
more info for mower

Hi Cheese, thanks for answering.
It is an overhead valve 2 cylinder, 20hp,briggs & stratton,model 460707.
Would the valves being out of adjustment make it so the starter even with a truck battery boosting it unable to even turn the crank to try and start. The engine won't even budge like when the battery is too low or dead to turn the starter.
Thanks again for answering.
Tim

 
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10-18-02, 07:36 PM   #4  
Hmmm...no, if the valves were too loose, then the engine would still try to turn a bit, just hanging up on the compression stroke a bit. I don't think valves are the problem here. Have you verified visually that the starter gear is in fact jumping up and contacting the gear on the flywheel? Could the gear be jammed in there? That happens fairly often. Short of that, I would say you may have a starter problem. If it turns out to be a bad starter, don't toss it and buy another. We'll rebuild it if it's not damaged badly. New ones run $120.00 and up. Check it out good and make sure all your connections are tight, although if it is humming, I would think all connections to be OK.


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10-19-02, 08:58 AM   #5  
khougi
mower

HI again,
I checked to make sure the starter gear is jumping into place and makeing an attempt to turn the main gear when I took the houseing off the engine, it does as it should but I believe we are on the right track. The starter may have just gone weak like I've experienced when working on cars in the past. How would I verify this, could I take it off and go to an auto supply where they check starters for cars?
Thanks again
Tim

 
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10-20-02, 12:16 AM   #6  
A common problem with the BriggsStraton is with the solenoid.

The motor might be fine...........

Try taking a wire from the positive term of the battery to the lead on the starter. A little sparky, but it works (I use a piece of 12ga house wiring) If that's it, tighten the two terminals from the battery and starter on the solenoid (disconnect batt first).

 
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10-20-02, 12:23 AM   #7  
Forgot to add.......but you probably know,,,,,,,,


The solenoid on the Murray is directly behind the motor on the frame cross-member underneath the steering wheel.

The starter is on the right side of the engine, right out in the open and very easy to get to.

If you're trying to start it that way, make sure your brake is engaged and key on so you don't have to sit on the seat or hold the brake to start it.

I think the odds are high that the solenoid is the problem. Like I mentioned, most often just needs tightening. Not too tight!!!! Its a copper stud and nut, so go easy.

 
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10-20-02, 12:30 AM   #8  
Geez, don't mean to write so many, but keep thinking of my experience with these things.

Also saw some strange things surrounding the starting when there was solenoid problems........Everything looked fine, tight, the weather was good, but still the thing just "clunked" when I tried to start, after starting perfectly just five minutes before.

Took off the positive wire on the battery, waited 5 seconds, put it back on, and it started great. Thought at the time that perhaps the relay wasn't fully releasing in the solenoid.

Started taking off that positive lead every time it happened, and after a few times, never had to do it again.

 
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10-20-02, 10:59 PM   #9  
Khougi...try cranking the engine with the spark plug removed. Does it turn then? If so, put mower in neutral, reinstall the plug and using a known-good battery and a set of jumper cables, connect the negative to the engine and the positive to the starter terminal. It will spark. If the engine turns, then the starter is good and you have problems in either the wiring, solenoid, etc... Make sure the connections at the battery are clean and tight....tight enough that you can't make the cable end move by hand. If the engine still doesn't turn, check to see if it begins to turn until a certain point then stops, or if it doesnt move at all. If it doesn't move at all, I would say you have starter problems. If it turns 1/4 revolution or so and then stops, then I would say you have valve lash problems.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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