Repairs Engine sputters and dies after warming up

HarleyP

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I have a John Deere X304 mower that I bought new 10 years ago. I regularly mow 2-3 acres of hilly, some steep, uneven ground, sometimes through tall grass. I had to replace the transmission 2 years ago. The symptom then was it was loosing a lot of power and speed (but the engine itself continued to be running fine). The "loosing power and speed symptom" has returned for the last couple of months (which makes me wonder about the quality of my repair, which was done by a non-authorized mower repair shop). But my biggest problem is a new symptom that started just yesterday. The mower starts and mows fine for about 10 minutes (engine sounds good, runs evenly, mower works fine) until the engine gets hot, then it starts to run unevenly, sputters and dies if I leave the mower unit running. If I disengage the mower unit, the engine would continue to sputter but not die, but it continues to run unevenly. I am able to "limp" it back to the shed. After letting the mower cool down, the same thing happens - about 10 minutes of mowing. Air filter is fine. I have not replaced the spark plug or fuel filter, but could if either of them is considered to be the culprit.
 

bertsmobile1

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Spend $ 15 and buy an in line neon spark tester.
Hook it up then go mow.
When the mower dies check the tester.
If it is flashing then you have a fuel delivery problem.
If the tester is not flashing you have an electrical problem.

If the tester is flashing dribble a very small amount of fuel into the carb ( or squirt some starter fluid ).
If it fires right up you have a fuel / carb problem.

Do that , get back & we will take it from there
 

ikeo

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Sounds like your gas cap vent hole is plugged. Next time it happens take the cap off and listen to see if there is a vaccum in the tank (air suction and hard to remove cap. Get a new gas cap if the vent hole is plugged. Another test is when it dies unscrew the cap and leave it loose enough that air can enter around the threads.
 

TJR345

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Sounds like your gas cap vent hole is plugged. Next time it happens take the cap off and listen to see if there is a vaccum in the tank (air suction and hard to remove cap. Get a new gas cap if the vent hole is plugged. Another test is when it dies unscrew the cap and leave it loose enough that air can enter around the threads.

If that doesn't solve the problem the coils are known to do this.My dad's x300 did the same thing and new coils fixed the problem.
 

ikeo

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If that doesn't solve the problem the coils are known to do this.My dad's x300 did the same thing and new coils fixed the problem.
My John Deere had the same problem, it would run until the vaccum in the tank kept the fuel pump from being able to pump gas to the carb. After letting it set for about 10 minutes the vaccum leaked away and the mower would start again and run for another 10 minutes. If that is the problem it will ruin the fuel pump if you don't fix it fast and then you will have to replace the fuel pump too. Don't let it go long enough for that to happen. Loosen the cap or buy a new one before you mow again. If the cap is loose enough the motor will not die when hot if the vent hole is the problem. It doesn't cost anything to try this first.
 

TJR345

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My John Deere had the same problem, it would run until the vaccum in the tank kept the fuel pump from being able to pump gas to the carb. After letting it set for about 10 minutes the vaccum leaked away and the mower would start again and run for another 10 minutes. If that is the problem it will ruin the fuel pump if you don't fix it fast and then you will have to replace the fuel pump too. Don't let it go long enough for that to happen. Loosen the cap or buy a new one before you mow again. If the cap is loose enough the motor will not die when hot if the vent hole is the problem. It doesn't cost anything to try this first.

Yes I know I'm agreeing with you,but if that doesn't work the coils cause the same problem when they get hot.
 

bertsmobile1

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Yes I know I'm agreeing with you,but if that doesn't work the coils cause the same problem when they get hot.

Which you verify with the neon plug tester suggested back in the first reply.
The OP has not responded so he either is too buisy or went elsewhere.
 
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