Engine Stumbling engine.

[bobbwsny]

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.

Appreciate your replies. I checked 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. If the coil went bad after getting warm wouldn't these readings not be within range?

 

[Fish]

No, I am with checking the valve gaps first.

 

[Exracer]

Appreciate your replies. I checked 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. If the coil went bad after getting warm wouldn't these readings not be within range?

I would think yes on the coils after getting hot. The reading would change.

 

[dwissinger]

I believe it is the ignighter. They short out when they get hot , then work again when cool.

 

[Hammerdown]

Appreciate your replies. I checked 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. If the coil went bad after getting warm wouldn't these readings not be within range?

Hell Bob
It sure sound's Like and Ignitor Ignition Moduel issue. I happen to have a good one I Pulled off a running engine if you need it let me know I would sell it for $25.00 Plus $5.00 shipping charges. Regards, Hammerdown

 

[Exracer]

I have found out over the years you can do all the coil resistance test you want and it will not prove if a coil is defective unless it is completely open. The sad truth of this is, a known good coil to try is the only reliable test for a job done right the first time.

 

[primerbulb120]

I had a similar problem on an old Craftsman wheeled weed trimmer. At full throttle, the engine would start, run fine for a few minutes, and then stall as if it had run out of gas. I tried it at half throttle and the problem disappeared. It turned out that one of the passages in the carb was partially restricted. This restricted the amount of gas coming into the float bowl. The gas was not supplied fast enough for the engine to run at full throttle, but there was enough for it to run slowly. This happened after I had repeatedly cleaned the carb. Check the passages leading to the float bowl to make sure they are all clear.

 

[SteveHaller]

What was the ultimate root cause and resolution of this issue?

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.

 

[bertsmobile1]

I would think yes on the coils after getting hot. The reading would change.

YOU CAN NOT TEST A MODERN COIL WITH AN INBUILT TRIGGER UNIT WITH AN OHMETER

You can check the secondary windings but if the trigger unit is duff it still will not run.
The minimum gear needed to test it is a rising voltage signal generator & an ossiliscope and they need to be good ones so expect to pay around $ 5,000 to $ 12,000 for them.
OR just replace the coil

 

[bertsmobile1]

I have found out over the years you can do all the coil resistance test you want and it will not prove if a coil is defective unless it is completely open. The sad truth of this is, a known good coil to try is the only reliable test for a job done right the first time.

Correct