Cub Cadet XT1 stumbling/sputtering

[Gomi_otaku]

Couldn't find anything in a search- my XT1 has started running odd when driving it around or idling. I tried driving it down the street yesterday for a nice smooth run with no bumps to throw off the seat sensor or affect the speed.
When I'm driving it acts like the governor is going up and down- bwa bwa BWAAA bwa bwa. Running down the street I could count 5 seconds then it would start "stumbling" for 2 seconds, then 5 seconds smooth again. I say "smooth" but it sounds lean to me, more of a sharp ignition sound.
Now, I run this thing year round, so gas is constantly being added new, nothing sitting around without additive. I've got about 83 hours on it in 2 years. I pull a small cart a lot, sometimes with a 60# hay bale in it but usually much less load. It runs like this whether it's got the cart on or not.
But- when I start mowing, it doesn't "cycle" like that- runs consistent, just with that more sharp ignition sound. I feel like the ignition sound should be less "harsh"
Probably way too much explanation, but let me have your ideas!

 

[tomplum]

On these the first thing I check on these is fuel flow out of the tank and look for debris that could plug the outlet. Strange, but I clean a few of these tanks a season. Also the roll over valve on top of the tank doesn't always vent and if a non fuel pump model, they can't always deal with a restrictive fuel filter. The XT 1 could have various engines in it. Smooth under load and hunting w/o many times though will indicate a blockage in the low speed circuit of the carburetor. Spark plug terminal, carb solenoid terminal and battery terminals should be secure. A few things for you to chew on. Welcome to TBN.

 

[Roadworthy]

Tom had some great suggestions. You say nothing sitting around without additive. What additive? If you're open to a change there I suggest Sea Foam. You can go by instructions on the can but initially you may wish to use more Sea Foam until your problem clears. If it's blocked carburetor passages this could clear them. Don't worry about too much Sea Foam - you can easily go past a fifty percent mix with no issues.

 

[5030]

Gunked up carb. Remove it, take it apart and clean it. I've been using a heated ultrasonic cleaner with Chem Tool in it for years to clean gunked up carbs.

 

[Gomi_otaku]

On these the first thing I check on these is fuel flow out of the tank and look for debris that could plug the outlet. Strange, but I clean a few of these tanks a season. Also the roll over valve on top of the tank doesn't always vent and if a non fuel pump model, they can't always deal with a restrictive fuel filter. The XT 1 could have various engines in it. Smooth under load and hunting w/o many times though will indicate a blockage in the low speed circuit of the carburetor. Spark plug terminal, carb solenoid terminal and battery terminals should be secure. A few things for you to chew on. Welcome to TBN.

I suppose if the rollover isn't venting, a quick and dirty test would be to drive with the fuel cap off or loose. All connections look secure, this symptom is so rhythmic it feels like a sensor issue (I work on Volkswagens) and the system feels like it is "hunting" up and down. I read on a Google search (so not sure what site) that misfires (which happen when shutting off with the throttle set too high) can cause the flywheel shear pin to deform without shearing, which I guess could throw off the ignition timing. I may try the Seafoam, I'm so busy lately I don't want to have to tear the carb apart to clean jets.

 

[Gomi_otaku]

Well, runs the same with the cap cracked/off. It's the Intellipower model so a fully electric carb, no way to even remove the bowl so I guess I'll start with Seafoam first before I look up some diagrams for tearing it apart.

 

[Blue14]

Just a suggestion, have you changed the inline fuel filter. On my XT-2 this past spring started sputtering off and on with about 160 hours on it and I thought maybe some fresh gas that did not help so I changed the fuel filter and its running like new again. I also never use any additives in my fuel gas powered equipment. Good luck on finding the problem.

 

[tomplum]

Some EFI models had issues with the connector snapping in fully at the ECU. My normal on these first is to check the pins in the connector to know that they are secure, clean and snap into place at every connector.

 

[Gomi_otaku]

Well, I replaced the fuel filter and spark plug with no change. Started to remove the carb but realized it couldn't be opened to clean the bowl- which involved disconnecting the module, so I know it was plugged back in securely. It's been at the factory service center since last week, waiting to hear. Hoping they total it out and give me full credit toward an XT2 with a real throttle control.

 

[Gomi_otaku]

Just to update- the one thing I didn't try was pulling off the air filter and running it. Well, the guys at the shop knew right away that was what the issue was, and replaced the filter without charging me a hefty idiot tax in diagnosis.
Turns out the Intellipower are pretty sensitive to airflow, and even if you take your filter out, brush off the outer foam pre-filter, and the main filter LOOKS ok, it could still be clogged.
I'm back up and running through 20" pasture grass.