Walk behind JOHN DEERE JX75 21" TROUBLESHOOTING

Gilbertwright49 · Apr 25, 2013

I have a JX75 self-propelled walk behind mower. I have had it for several years and it has performed superbly. It was my primary mower when I had a small yard but a few years ago I moved to a lot more land and it has been my trim mower since.

The mower starts ok but when I engage the blade and the drive wheels, it runs a few seconds to minute and then starts to die. If I immediately disengage all drives, it will usually recover; sometimes backfiring a time or two before running normally. Very recently, it started to die after a few minutes of just idelling. What I have checked is:

Changed the gas.
Checked gas flow to the carburator - it seems fine.
Checked the plug and spark - blue white spark when tested.

Has anyone experienced this type of a problem?
Does anyone have any suggestions for further testing or have an idea of how to fix it?

Best regards and Thanks in advance for any responses.

Gil

THansen · Jun 2, 2013

Gilbertwright49 said:
I have a JX75 self-propelled walk behind mower. I have had it for several years and it has performed superbly. It was my primary mower when I had a small yard but a few years ago I moved to a lot more land and it has been my trim mower since.

The mower starts ok but when I engage the blade and the drive wheels, it runs a few seconds to minute and then starts to die. If I immediately disengage all drives, it will usually recover; sometimes backfiring a time or two before running normally. Very recently, it started to die after a few minutes of just idelling. What I have checked is:

Changed the gas.
Checked gas flow to the carburator - it seems fine.
Checked the plug and spark - blue white spark when tested.

Has anyone experienced this type of a problem?
Does anyone have any suggestions for further testing or have an idea of how to fix it?

Best regards and Thanks in advance for any responses.

Gil

Gil,

I have had a similar problem with my JX75. I found problem in the carb. The first thing I found was the main jet was partially plug. Second was the needle valve was bad. Remove the bowl on the carb. The tube holds the main jet that is set inside. Screw out the main jet and run a wire the size of a bread twisty or smaller the very small hole. There is another tube inside the main jet tube that should drop out. Make sure all holes in the tube are open. Shoot carb cleaner through all openings throughout the carb. Next pull the pin that holds the float in place. Remove the needle valve and shoot carb cleaner in the seat hole. Carb cleaner should shoot out the fuel inlet tube. Look at the point of the needle valve. Look closely to see if it is comes to a perfect point. If you see ridge replace it. My JX75 would not idle very long and would quit running. It also leaked gas out of the carb when not running. The needle valve had a ridge on the rubber point and would not seat properly. This would cause the engine to flood and stop when idling. Running at full throttle the engine would misfire during a load on it. Cleaning the main jet and replacing the needle valve did the trick. Runs like it was brand new. Hope this works. Tom

PJ · Jun 3, 2013

Gilbertwright49 said:
I have a JX75 self-propelled walk behind mower. I have had it for several years and it has performed superbly. It was my primary mower when I had a small yard but a few years ago I moved to a lot more land and it has been my trim mower since.

The mower starts ok but when I engage the blade and the drive wheels, it runs a few seconds to minute and then starts to die. If I immediately disengage all drives, it will usually recover; sometimes backfiring a time or two before running normally. Very recently, it started to die after a few minutes of just idelling. What I have checked is:

Changed the gas.
Checked gas flow to the carburator - it seems fine.
Checked the plug and spark - blue white spark when tested.

Has anyone experienced this type of a problem?
Does anyone have any suggestions for further testing or have an idea of how to fix it?

Best regards and Thanks in advance for any responses.

Gil

Hi the backfiring makes me think that the timing has moved and the only way it can move is if it shared the key on the flywheel. you need to remove the flywheel to see if the key is shared you think you can do that?

PJ

Gilbertwright49 · Jun 3, 2013

PJ said:
Hi the backfiring makes me think that the timing has moved and the only way it can move is if it shared the key on the flywheel. you need to remove the flywheel to see if the key is shared you think you can do that?

PJ

Thanks for the info and I can remove the flywheel but the key is not the problem. It has to do with the fuel supply. I changed the plug, put on new fuel lines, new fuel filter, and clened the fuel shutoff. Running great.

Gilbertwright49 · Jun 3, 2013

THansen said:
Gil,

I have had a similar problem with my JX75. I found problem in the carb. The first thing I found was the main jet was partially plug. Second was the needle valve was bad. Remove the bowl on the carb. The tube holds the main jet that is set inside. Screw out the main jet and run a wire the size of a bread twisty or smaller the very small hole. There is another tube inside the main jet tube that should drop out. Make sure all holes in the tube are open. Shoot carb cleaner through all openings throughout the carb. Next pull the pin that holds the float in place. Remove the needle valve and shoot carb cleaner in the seat hole. Carb cleaner should shoot out the fuel inlet tube. Look at the point of the needle valve. Look closely to see if it is comes to a perfect point. If you see ridge replace it. My JX75 would not idle very long and would quit running. It also leaked gas out of the carb when not running. The needle valve had a ridge on the rubber point and would not seat properly. This would cause the engine to flood and stop when idling. Running at full throttle the engine would misfire during a load on it. Cleaning the main jet and replacing the needle valve did the trick. Runs like it was brand new. Hope this works. Tom

Tom, Thanks for the reply and information. I think you are right and the carb is the problem. I changed the plug, put on new fuel lines, new fuel filter, and cleaned the fuel shutoff valve. It started up and ran like a new one - - - - for about an hour running time. Now it is getting sluggish. I will do as you suggested when I get some time. In the meantime, I got the issues resolved with the Cub cadet zero turn and can use it, though the JD is best for the new grass I have in the back yard.

Thanks again for the post.

Gil

Walk behind JOHN DEERE JX75 21" TROUBLESHOOTING

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