What to Do If Your Kubota Zero Turn Mower Won’t Go Forward or Backward
There could be a number of reasons why your zero-turn has stalled and you have no idea what to do about it. I have made a checklist of possible places to start looking for the source of the issue. If you try to pull your lawnmower, the transmission could get damaged.
In the event that the drive release levers are in the operational position, the hydro belt is worn, the tensioner pulley is broken, the idler arm spring is missing, the hydraulic oil level is low or heated, or air is trapped in the hydraulic system, the Kubota zero-turn will not go forward or backward.
When tinkering with the hydraulics of your lawnmower, make sure to take the necessary safeguards. Don’t touch the transmission until it’s cooled down, and keep your distance from the sizzling hydraulic fluid.
To begin maintenance or repairs, turn off the ignition and disconnect the spark plug wires.
Table of Contents
Top 7 Causes Your Kubota Zero Turn Is Stuck
Release Levers Are Not Engaged on Kubota Zero-Turn Tractor
Putting the gearbox bypass levers in the “bypass” position releases the hydros, allowing you to push the mower.
The hydro levers must be engaged in order for the wheels of a Kubota zero-turn to move. On the left and right sides of the zero-turn are the rods (Z100, Z200, and Z400 series) or levers (Z700 series) used to control the direction of the vehicle.
To use the mower’s driving levers, these levers must be in the “working” position.
The drive belt on your Kubota zero-turn pump is either frayed or broken.
If the drive belt on your zero-turn is worn, its performance may suffer. Make that the Kubota drive belt is still on and snugly wrapped around the appropriate pulleys.
Any visible symptoms of wear on the belt necessitate its replacement.
Tensioner Pulley Failure on a Kubota Zero Turn
Either the tensioner pulley or its bearing can fail. The strong plastic used to make most tensioner pulleys eventually wears out or cracks.
If a pulley’s bearing is bad or it’s just worn out, you should replace it. Always keep the tensioner arm well lubricated to prevent it from becoming stuck.
One of the Kubota Zero Turn’s Idler Arm Springs is Missing
The driving belt for the pump is under stress thanks to the idler spring. Get a new one if your Kubota’s old one is broken or missing its spring.
Your Kubota Zero Turn’s Hydraulic Fluid Is Low.
Maintenance on your Kubota’s transmission system, including frequent replacements of the hydraulic fluid, is essential to ensuring its optimal performance. If the hydraulic fluid in the gearbox is low or old, your zero-turn may not move at all or operate extremely weakly.
It is best practice to check the mower’s fluid level just before using it when the oil is cool. Check the fluid levels by first wiping the area around the caps.
When it comes to the hydraulic system, dirt is a common culprit in a breakdown, therefore it’s important to avoid getting any into the system at all costs.
When the hydraulic oil level in your system drops below the full mark on the dipsticks or overflow tanks, you must replenish the fluid by adding more of it (depends on the model of your Kubota).
A Kubota zero-turn requires periodic flushing of its hydraulic fluid to ensure peak performance.
| Model | Capacity | Transmission Oil |
|---|---|---|
| Z121SKH, Z122EBR, Z122RKW, Z125SKH | 5.1 Qts | SAE 20W-50 |
| Z231BR, Z231KH, Z231KW, K251BR, K251KH | 5.1 Qts | SAE 20W-50 |
| Z411KW, Z421KW, Z421KT | 5.1 Qts | SAE 20W-50 |
| Z723KH, Z724KH, Z725KH | 6.3 Qts | Parker HT-1000 |
| Z724XKW, Z726XKW, Z751KWi, Z781 | 7 Qts | Parker HT-1000 |
When you discover your hydraulic oil level is low, it is also wise to inspect for hydraulic fluid leaks. When dealing with hydraulic fluid leaks, it is best to contact a Kubota turf dealer for assistance.
Burning Hydraulics on Your Kubota Zero Turn
Lack of or poor quality hydraulic fluid causes the Kubota zero-turn to overheat due to increased friction.
More serious problems may be the cause of your Kubota mower’s hot hydraulic fluid.
If your lawnmower is leaking fluid from the hydraulic pump or starts up and operates normally when cold but shuts down while heated, you should take it to a Kubota dealer.
Your Kubota Zero Turn Mower Has Air in the Hydraulic System.
Your Kubota zero-turn may move slowly or not at all if air is stuck in the hydraulic system. It is necessary to bleed the air out of the hydraulic system after changing the fluid or whenever the transmission is opened.
The zero-turn may make a squeaking sound if there is air trapped in the mechanism. Further, it raises the temperature of the oil, which can lead to greater expansion than usual.
Getting the air out of the hydraulics:
Most Kubota zero-turns have a feature that allows air to be released from the hydraulic system by simply lifting the rear drive tires. If you don’t have the means to lift the drive tires, you also can conduct the test so long as it is done in a clear, open location.
Before proceeding, check to see that the transmission has adequate oil.
Start the engine after opening the bypass valves and releasing the parking brake, if applicable. Slowly advance and then reverse the drive levers about six times.
Do not leave any open bypasses. Turn the drive levers forward and backward roughly six times while holding the throttle wide open. Keep doing this until the tires are no longer making an abnormal amount of noise and moving at typical rates.
When you’ve finished deflating the tires, turn off the car and put on the parking brake. If you have expansion tanks, check the oil level to make sure it’s at the FULL COLD line. If it’s below this line, add oil till it is.
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