Engine Stumbling engine.

bobbwsny

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Hello,

I have a John Deere 14SE walk behind mower from the mid 90's that I acquired a year ago or so. Can't believe how solid this thing is built, but unfortunatly I can't get the engine, a Kawasaki FC150v, running properly. It starts right up, runs great for about 10 minutes, then starts stumbling. The engine seems to be getting too much fuel, or the electrical system is breaking down. I have had the carb off and apart many times, it is clean, even took the carb to a mower repair shop owned by a friend, they took it apart and could fine no problem with it. The carb and choke linkages are adjusted fine, the carb float seems to be working fine, the needle seems to be seating properly. Have tried many different brands and proper new spark plugs with the same results, they all turn black right away. Tested the OHM resistances in the coil, both primary and secondary as per the John Deere manual, and they are right on both before and after the stumbling conditions occurs. I replaced the fuel line, made sure everything was clean, but like I wrote, when the stumbling occurs it looks like an over-rich condition. Tried loosening then actually replaced the gas cap thinking there may be some type of vapor lock due to the gas cap to no avail. I am usually pretty good with these things but I gotta admit I am about to wit's end with this one. Anyone have any suggestions? Thanks.
 

Fish

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When it starts stumbling, remove the air filter.
 

bobbwsny

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When it starts stumbling, remove the air filter.

Hello Fish,
Thanks for your response. I did try running it by removing the air filter, made no dif. Still stumbled real bad, so bad I could not use it. Appreciate your input, any other suggestions are appreciated.
 
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Hello Fish,
Thanks for your response. I did try running it by removing the air filter, made no dif. Still stumbled real bad, so bad I could not use it. Appreciate your input, any other suggestions are appreciated.



Have you checked, and cleaned the magnet on the flywheel? How are the valves on adjustment?
 

bobbwsny

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Yes, check the valve adjustment. Here are the specs.

Kawasaki Small Engine Intake and Exhaust Valve Clearances


Did this happen all of the sudden, or did someone have the carb apart? Or someone worked on it? Hit a stump? Etc?


Thanks for the reply. I will check the valve adjustments. This happened all of a sudden, did not hit anything, did not take carb or anything else apart until I started having this problem.
 

PJ

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Hello, I have a John Deere 14SE walk behind mower from the mid 90's that I acquired a year ago or so. Can't believe how solid this thing is built, but unfortunatly I can't get the engine, a Kawasaki FC150v, running properly. It starts right up, runs great for about 10 minutes, then starts stumbling. The engine seems to be getting too much fuel, or the electrical system is breaking down. I have had the carb off and apart many times, it is clean, even took the carb to a mower repair shop owned by a friend, they took it apart and could fine no problem with it. The carb and choke linkages are adjusted fine, the carb float seems to be working fine, the needle seems to be seating properly. Have tried many different brands and proper new spark plugs with the same results, they all turn black right away. Tested the OHM resistances in the coil, both primary and secondary as per the John Deere manual, and they are right on both before and after the stumbling conditions occurs. I replaced the fuel line, made sure everything was clean, but like I wrote, when the stumbling occurs it looks like an over-rich condition. Tried loosening then actually replaced the gas cap thinking there may be some type of vapor lock due to the gas cap to no avail. I am usually pretty good with these things but I gotta admit I am about to wit's end with this one. Anyone have any suggestions? Thanks.


An over rich condition means lack of air to the mixture. I would look and I know you looked at the carburetor. What about the air passage way to the air jet mixture adjustment somehow it is preventing air to get into the mixture air mixture screw turned closed cannot be a big thing have a look

Regards
PJ
 

redfish9

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when this happens to my exmark it's most always a bad coil
 

Exracer

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The coil, or the igniter?

I'm with Fish since runs fine on start up and takes 10 minutes to fail the coil is suspect if you ask me. They get hot and open causing misfire.
 
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