Cub Cadet RTZ50 Stumbling Under Load

[rhuba]

My 2006 RTX50 (model 17AA5D7P710) with Kawasaki engine has developed a frustrating problem. When the mower is under a load, the engine starts stumbling-cutting out. I noticed that there didn't seem to be any fuel in the filter. I replaced the fuel pump and all the fuel lines after draining and cleaning the tank. Now there is fuel in the filter at all times even when engine is stumbling. I swapped the carburetor with the original, which I had replaced to troubleshoot a hard starting problem. (It didn't fix that issue, so I believe the carb is good.) It seems to run all right unless it is under load. While it is stumbling, there is no evidence of smoke indicating running rich. My next step is to start throwing money at it, ignition modules, etc. I would rather not do that. Anyone run into this problem before? I would appreciate any help.

 

[Scrubcadet10]

slowly close the choke when it starts stumbling, see what happens.

 

[Bertrrr]

Clean the carb

 

[Tiger Small Engine]

My 2006 RTX50 (model 17AA5D7P710) with Kawasaki engine has developed a frustrating problem. When the mower is under a load, the engine starts stumbling-cutting out. I noticed that there didn't seem to be any fuel in the filter. I replaced the fuel pump and all the fuel lines after draining and cleaning the tank. Now there is fuel in the filter at all times even when engine is stumbling. I swapped the carburetor with the original, which I had replaced to troubleshoot a hard starting problem. (It didn't fix that issue, so I believe the carb is good.) It seems to run all right unless it is under load. While it is stumbling, there is no evidence of smoke indicating running rich. My next step is to start throwing money at it, ignition modules, etc. I would rather not do that. Anyone run into this problem before? I would appreciate any help.

Can you describe the “stumble” more specifically?

 

[rhuba]

Stumbling refers to loss of RPM, sounds like it is going to die, but doesn't completely shut down. I have tried closing the choke and it does die at that point. By removing the load by stopping travel or shutting off mower, it recovers. When I swapped the carb, I assumed that I eliminated the carb as the problem since the original carb didn't have the issue. I will try cleaning when I get the opportunity.

 

[Scrubcadet10]

Even though your filter stays full.. next time it starts to stumble, loosen the gas cap, or when you go mow, just start with the fuel cap loose and see if it does it

 

[rhuba]

I have removed the gas cap and it doesn't have any effect. I have also checked all of the deck pulleys and the mower clutch to make sure there aren't any binding up. The mower clutch is fully engaging and the brake is fully disengaged.

 

[Craftsman Garage]

Adjust the valves

 

[StarTech]

Very possible that the engine is just running on one cylinder. V-twins can run very smooth on one cylinder until under a load.

 

[Craftsman Garage]

Yeah, that's happened to me a couple times and I never knew it Iol