JD X500 Engine Stops and Backfires

[truman99]

My JD X500 was purchased in 7/2013. and now has 300 hours. Mower repeatedly shuts off while mowing and backfires; sometimes cranks back up and sometimes need to wait 10 - 15 minutes for engine to start. This problem started late October 2018. I changed the spark plugs and problem was solved. I was able to complete my final mowing for 2018 CY.

On April 1, 2019, I had a John Deere dealer perform a 'Deluxe Service Special' including engine tune up, change engine oil/filter, lube chassis, service battery, check charging system, etc. Tractor meter was at 300 hours.

At 310 hours, the engine began stopping and backfiring repeatedly (same as Oct 2018); about every 10 - 15 minutes. I called my John Deere dealer for servicing and was told it would be 3 weeks until the tractor would be fixed. 3 weeks was unacceptable. I found an independent small engine service company that disassembled the carb; cleaned carb; re-assembled carb; set valve clearances,; replaced OHV gaskets; set engine timing; tested OK. After all this work, I cut grass for about 2 hours and had 6 engines/backfires. I was able to complete the mowing.

I found on 'Justanswer.com' this identical problem in a Sept 2013 post and was able to contact the JustAnswer.com Technician that helped that customer. His solution was to 'replace the fuel solenoid in the carburetor base'.

I am not a mechanic. I would appreciate replies from forum members that have experienced this problem on JD X500 tractors and what your solution was.

Thank you in advance.

 

[tomplum]

Welcome to the TBN. If it comes down to swap a part to save frustration, put on an ECU. This assumes that the ignition is intermittently being cut. A reminder that sometimes we create these backfires by attempting to keep it running. Verify a good fuel flow from the tank.

 

[crazyal]

I would buy a simple inline spark tester that plugs into the spark plug. When the engine is running you'll see it flash. When it won't start check it. If there's no glow you have an electrical problem. Once you know it's a fuel problem I think you can replace the solenoid with a bolt to test it. I've heard of people cutting off the needle so gas can always flow. If you do it I wouldn't leave it this way. Another simple test is to get a 12v electrical tester and connect it up to the wire going to the solenoid so you can mow with it in place. If the light shuts off then you have an electrical problem that's causing the solenoid to shut off.

My personal opinion is that the solenoid wouldn't cause it to backfire. Typically backfires are unburnt fuel getting into the hot muffler where it's burnt. The solenoid shuts the fuel off so when you turn the engine off (by turning off the spark) the pistons don't keep drawing in fuel and pushing it into the hot exhaust. If the solenoid is shutting off it should be doing just the opposite. The engine should just die and not start until it opens again. I'm not an expert so I could be wrong. A backfire seams like a spark issue to me. You have it then you don't. When you don't unburn fuel is getting into the exhaust.

 

[jgayman]

I would buy a simple inline spark tester that plugs into the spark plug. When the engine is running you'll see it flash. When it won't start check it. .

Probably need two of them since this is a two cylinder engine.

 

[Nesh]

My x540 would stall at anytime and backfired so I prayed for the answer. I then went online and read other folks having the same problem and the first story I read was of a person solving it by replacing the Electronic Computer Unit, so I squeezed the connector to it and it started. The next morning I sprayed DW40 on both ends of the ECU connectors then reconnected them and it has not stalled since. Thank God...

 

[Richard001]

Nesh - welcome to TBN

Richard