Cub Cadet troubleshooting

[mawil1013]

Is this even covered here?

Got an 12 year old cub cadet, basically all ok except motor stalls out in reverse. Cleaned plug, checked air filter, oil still clean.

[JimmyMechanic]

Yes, definitely covered here — and stalling specifically in reverse (not forward) is actually a pretty recognizable symptom on these, since you've already ruled out the usual ignition/airflow suspects. A couple of things worth checking, roughly in order of how common they are:

• Reverse Safety System (RSS) / PTO interlock — if your model has mower deck engagement tied into a reverse safety switch (many Cub Cadets do, to prevent backing over something with the blades running), a dirty, stuck, or misadjusted RSS switch can kill the engine the moment you shift into reverse with the deck engaged. Try backing up with the PTO/blades disengaged — if it doesn't stall that way, this is almost certainly your culprit. The switch is usually near the mower deck lift arm or under the seat area; it just needs cleaning or a minor adjustment in most cases.
• Fuel pickup position — if the tank is running low, some of these have the pickup tube positioned so that tilting backward (which happens briefly when you shift to reverse, especially on any slope) can momentarily uncover it and starve the carb. Worth topping off the tank and seeing if the problem changes.
• Seat or brake safety switch — less specific to reverse alone, but worth a wiggle-test while the engine's running: gently shift your weight or flex the seat and see if it stumbles. A worn seat switch contact is a common stall culprit on machines this age.

Since you've already cleared the plug, filter, and oil, I'd start with #1 (test with the deck disengaged) since it's the cheapest to rule out and matches your symptom exactly.