J.D. X300 loses fire in short time mow

Hayward51

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I have been pulling my hair out over this 'overheating' (?) John Deere. It has a Kawasaki 600V-as21 engine and will shut down usually after 15-30 min. mowing. My first thought was coils. I bought new Kawi coils. same result. I removed anti-backfire solenoid. same result. I replaced spark plugs with new and colder, pulled sheet metal and blew out around engine, adjusted valves, installed larger fuel filter, cleaned carb., and even sharpened the blades. Is it possible a safety switch could be cutting the spark out after heating up ? I just ran out of options ...
 

sgkent

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3 things make an engine run

air/fuel ratio
compression
spark

Figure out which one is missing when it dies and then chase that path. Shotgun approach works sometimes but at this point figure out what is missing. You can get a plug tester or timing light to see if the plug fires when it dies. If spark is missing it can be anything in the ignition or ignition supply side. If you have spark then do a quick compression test. Next is maybe something in the fuel supply, tank venting etc..
 

Hayward51

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3 things make an engine run

air/fuel ratio
compression
spark

Figure out which one is missing when it dies and then chase that path. Shotgun approach works sometimes but at this point figure out what is missing. You can get a plug tester or timing light to see if the plug fires when it dies. If spark is missing it can be anything in the ignition or ignition supply side. If you have spark then do a quick compression test. Next is maybe something in the fuel supply, tank venting etc..
Thanks for your reply. I have a spark tester and had it on the mower with me. It's definitely losing spark. When it cools down, maybe 5-10 min., it will fire up and run again for maybe 5 minites and shut down again. Fuel pump is working the entire time. Not a fuel problem. It quits like you turned the key off.
 

Hammermechanicman

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Not familiar with x300 wiring offhand but does your mower have a time delay module? It is part of the JD wiring and not the Kaw engine.
 

bertsmobile1

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Next step is to remove the kill wires from the coils and see if the problem persists
This will show if it is an engine problem or mower wiring problem
Let us know what happens
 

Hayward51

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Not familiar with x300 wiring offhand but does your mower have a time delay module? It is part of the JD wiring and not the Kaw engine.
I wasn't familiar with this model until this week. It belongs to an elderly neighbor and it does have a delay after you switch the key to OFF.
 

Hayward51

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Next step is to remove the kill wires from the coils and see if the problem persists
This will show if it is an engine problem or mower wiring problem
Let us know what happens
I will try that today and let you know. Thanks.
 

Hayward51

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Thanks for the tip on disconnecting kill wire. I mowed for about 30 min. when it quit the first time and fired back up when I placed spark detector in line. I left it on and went mowing, it died 5 min. later. It would not start back up. I verified no spark again and disconnected kill wire. It fired up immediately and mowed for another 30 min. without a problem. Is the ECM the problem ? What else would act like that ?
 

Hayward51

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Thanks for the tip on disconnecting kill wire. I mowed for about 30 min. when it quit the first time and fired back up when I placed spark detector in line. I left it on and went mowing, it died 5 min. later. It would not start back up. I verified no spark again and disconnected kill wire. It fired up immediately and mowed for another 30 min. without a problem. Is the ECM the problem ? What else would act like that ?
The time delay modules die all the time. If you have a piece that looks like this try changing it and see what happens
Thanks for info, I didn't find anything that looked like that under the dashboard.
 
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