9 Kubota GR2120 Problems and Solutions

Kubota zd1211 Problems

When you set out to mow your lawn, the machine you use determines the results you get. So, you need a mower that is powerful, efficient, manoevarable, and easy to use.

Kubota Gr2120 makes it on the list of the top tractors to consider for domestic and small commercial applications. This is a 21hp engine designed to mow both small and big lawns.

However, like other farm equipment, you should be aware of Kubota Gr2120 Problems. Besides, you need to know how to solve each of these problems.

Kubota GR2120 Problems

  • The engine Shuts Down unexpectedly
  • Exhaust fumes
  • PTO failure
  • Overheating Issue
  • Cranking issues
  • The starter doesn’t work
  • Transmission issue
  • Engine produces smoke
  • Steering Problem

Problem #1: The Engine Shuts Down Unexpectedly

Working with an engine that shuts down unexpectedly could be frustrating if you are new to using tractors.

Unfortunately, this is one of the nightmares you will encounter not once but on many occasions when mowing with Kubota Gr2120.

If you have never mowed with this tractor, it may be alarming. However, it is a minor issue that you can sort out without seeking help from experts.

So what causes the engine to shut down unexpectedly? Firstly, using poor quality or degraded fuel is the main cause of the problem.

If you keep the tractor in the store for a long time, the fuel breaks down into gummy deposits, and so its quality degrades.

Consequently, the engine will have difficulties utilizing such fuel hence shutting down without notice.


  • Siphon the old fuel, and refill it with new quality fuel.
  • Check and clean the air filter. If it is old, clogged, or worn out, replace it.
  • Check fuel lines for deposits and build-ups that restrict the fuel flow.
  • Check, clean, or replace old fuel filters.

Read: Kubota L3560 Concerns

Problem #2: Emits Exhaust Fumes

After some time, your tractor may start emitting colored smoke. This could make you nervous if it is the first time you are handling Kubota Gr120.

However, you do not need to get overly concerned. Just take note of the hue of the smoke and figure out an appropriate solution.

Black smoke indicates that the tractor is running on poor-quality fuel. It could also result from blocked air filters or an overfilled gas tank.

On the other hand, if the smoke is blue-white, it may be due to issues with the injection pipe or moist discharge valve.


  • If exhaust fumes are black, replace the fuel filters and the fuel. Also, don’t overfill the tank, and keep an eye on the fuel level.
  • Always check your air filters and, if necessary clean and change them.
  • For Blue-white smoke, reduce the load and warm up the muffler.
  • Also, inspect the fuel injection mechanism and repair or replace it if faulty.

Read: Kubota zd1211 concerns

Problem #3: Kubota Gr2120 PTO Failure

PTO dysfunction is a common issue with Kubota Gr2120. You will notice that sometimes the PTO shaft moves without sufficient contact.

This happens when the PTO is incorrectly engaged, so the shaft will not revolve. There are many causes of PTO malfunctioning.

The most noticeable one is when the hog does not work even you disconnect the PTO from the power source.

Related: Kubota M5 111 Concerns and Quick Solutions


  • Ensure the clutch packs are in good shape and consider changing them once you notice the PTO is faulty.
  • If the clutch parks are ok, the problem may lie in the PTO control valve. So carry out performance testing to help determine if it is in excellent shape. If the valve seals show signs of wearing out, consider changing them.

Problem #4: Overheating Issue

Overheating happens when the engine is subjected to more load than it can handle. For instance, putting too much load on the lower gear makes KubotaGR2120 overheat.

If left to overheat for a longer period, its functionality deteriorates. If the connection between the hoses and the radiator is improper, it exacerbates the problem.

Also, if there is an obstruction in the coolant, it causes overheating. The engine will also overheat if the cooling system is clogged. Overheating impacts the gasoline and compromises efficiency.


  • When the engine gets hot frequently, check the coolant level and refill it if possible.
  • Check the coolant’s connections and wipe the radiator base. You may also change the coolant and clean the system to remove obstructions.

See Also: Kubota L3901 Concerns and Quick Fixes

Problem #5: Cranking Issues

Cranking is a common problem in tractors and mowers. The motor may refuse to start or take a long time to start.

When it happens, and you have limited time to complete a project, it could inconvenience you or your customer.

The GR2120 tractor’s motor will exhibit the same problems if you dont take good care of it.

Besides, cranking issues will become prevalent if the tractor battery is dying or if there are bad connections. Some of the common causes of bad connections include rust and dust.


  • Taking good care of the battery, including checking connections and inspecting its state.
  • Inspect and fix problem minor issues in a timely manner.
  • Check and remove filth and rust using specialized cleaning products.
  • Test the tractor’s safety switches and ensure the voltage is right.
  • Change the battery and fix wires that are hanging loose.
Kubota GR2120 Problems and troubleshooting tips

Problem #6: The Starter Doesn’t Work

Most lawn tractors have issues with starting. Fortunately, you can fix these problems since they result from dirty terminal connections and dead batteries.

When the battery is faulty or dead, the starter will not work. Also, if the connections are loose or discontinued, the starter will not work.

The terminals, too, may corrode because of electrolyte leakage or hydrogen. When you overcharge the battery, the positive terminal may corrode.

It forms a bluish or greenish substance that inhibits the flow of electricity. This makes it difficult for the mower to start.

Related: Kubota Regen Concerns & Fixes and Solutions


  • If the battery is old, ensure to replace it.
  • You may clean the terminals with vinegar to enhance connectivity.
  • Check the connections, including keeping an eye on the corroded connection.

Problem #7:  Transmission Issue

A functional transmission system powers the tractor and allows it to move. The system comprises of a hydraulic motor that transfers power to the mechanical drive chain to thrust the mower forward.

But sometimes, the air gets into the system and impacts the hydraulic pressure. As a result, the tire pressure may not be sufficient to move the tractor forward.

Thus, if the transmission develops issues, it affects the hydraulic system and so the tractor will not move.

Further reading: Common Kubota B2601 Concerns


  • Check hydraulic lines and ensure they are no breaches that allow air to get into the system.
  • Check hydraulic oil levels and top up if they are low.
  • Check and repair the breaks if they contribute to the transmission issue.

Problem #8: Steering Problem

The steering wheel problem is one of the issues you will likely run into if you regularly operate GR2120. Fortunately, in most cases, the steering issue could be a simple one.

Therefore, you could fix it on your own. However, there are cases it may require a competent repairman.

Flat or unevenly inflated tires could make the tractor lean on one side. In such a scenario, controlling the tractor becomes difficult and challenging.


  • Check the transmission oil. If it is low, top it up.
  • Check the tires and ensure they have equal pressure. If they are uneven or any of them are flat, inflate them.

Problem #9: Smoke Coming from the Engine

If the engine produces a little smoke, you will need to check the problem even if the tractor is working fine. Often, it could produce white or blue smoke if the engine is burning off extra oil.

Also, a leakage could make the oil drips to fall on hot parts and burn off. In other cases, the problem could be a result of drive shaft leaks, cylinder rings, or head gaskets.


  • Check and repair the dull cylinder and the gasket.
  • Clean or replace air filters.
  • Use fuel stabilizers to keep the fuel fresh.

Kubota GR2120 Problems and Troubleshooting

The Engine Shuts Down UnexpectedlyPoor quality or degraded fuel, fuel degradation due to prolonged storage– Siphon the old fuel and refill with new quality fuel
– Check and clean the air filter.
– Check fuel lines for deposits and build-ups
– Check, clean, or replace fuel filters
Emits Exhaust FumesBlack smoke: poor-quality fuel, blocked air filters, overfilled gas tank<br>Blue-white smoke: issues with injection pipe or moist discharge valve– Black smoke: replace fuel filters, use proper fuel level.
– Check and clean air filters
– Blue-white smoke: reduce load, warm up the muffler, inspect and repair fuel injection mechanism
PTO FailureIncorrectly engaged PTO, faulty clutch packs, worn-out PTO control valve– Check and change clutch packs if necessary
– Perform performance testing on PTO control valve and replace worn-out seals
Overheating IssuePutting too much load on lower gear, improper connection between hoses and radiator, coolant obstruction or clogged cooling system– Check coolant level and refill if necessary
– Check coolant connections and clean radiator base
– Change coolant and clean the system to remove obstructions
Cranking IssuesFaulty or dying battery, bad connections (rust and dust)– Take care of the battery, check connections.
– Inspect and fix minor issues promptly.
– Clean terminals with vinegar, check corroded connections
The Starter Doesn’t WorkFaulty or dead battery, loose or discontinued connections, corroded terminals– Replace the old battery
– Clean terminals with vinegar
– Check connections and fix any issues
– Fix loose wires
Transmission IssueAir getting into the hydraulic system, low hydraulic oil levels, faulty breaks– Check hydraulic lines for breaches
– Top up hydraulic oil levels
– Check and repair breaks
Steering ProblemFlat or unevenly inflated tires– Check transmission oil levels and top up if necessary
– Check and inflate tires to equal pressure
Smoke Coming from the EngineBurning off extra oil, oil leakage, drive shaft leaks, cylinder rings, head gaskets– Check and repair cylinder and gasket
– Clean or replace air filter
– Use fuel stabilizers to keep fuel fresh

Kubota gr2120 vs john deere

Kubota GR2120 and John Deere are two well-known brands in the lawn tractor market.

The Kubota GR2120 offers reliable performance with its powerful engine but has been reported to have issues such as engine shutdown and PTO failure.

On the other hand, John Deere tractors are known for their durability and wide range of models to suit different needs.

John Deere tractors often have excellent steering capabilities and ergonomic designs for user comfort.


Is Kubota Gr2120 a good mower?

It’s with no doubt that Kubota Gr2120 is a good mower. It features a 21 HP engine designed for heavy-duty mowing tasks. The engine is attached to a thick 5/16 frame and features a powerful hydrostatic transmission through which the shaft drive and glider steer offer maneuverability.

Check out our in-depth Kubota lawn tractor reviews.

What are the main problems associated with Kubota Gr2120

PTO failure, transmission issues, engine shutting up unexpectedly, exhaust fumes, and cranking issues are the common problems affecting Kubota Gr2120. Other issues that are common in other mowers but which still afflict this lawn tractor include steering problems, starting issues, and engine overheating.

What engine does Kubota Gr2120 have

The Kubota GR2120 garden mower is fitted with Kubota D782 engine. This is a 0.8L three-cylinder engine with 2.64 in the cylinder bore and 2.9 in piston stroke. It is a powerful 21 HP engine capable of producing 21.2PS output power. Thus, the mower is comparable to Kubota bx series.

How should you store Kubota Gr2120 when not in use?

If you will not be using the mower for some time, you may want to store it in a garage. But before you store it, ensure to remove the battery and turn off the shut-off valve. Also, add fuel stabilizers or siphon the oil from the tank. If you don’t, the fuel will degrade and evaporate, leaving behind gummy residues.

Interesting read: Kubota Z421 Concerns & Quick Fixes

Kubota gr2110 problems

  1. Transmission Issues: Some users have experienced issues with the transmission system, such as difficulty shifting gears or losing power.
  2. Steering Problems: There have been reports of steering issues, including stiffness, inconsistent steering response, or difficulty maneuvering the tractor.
  3. PTO Malfunction: The power take-off (PTO) mechanism has been known to malfunction in some cases, resulting in the inability to engage or disengage attachments properly.
  4. Electrical Problems: Users have reported electrical issues, including problems with the wiring, faulty switches, or intermittent electrical failures.
  5. Mower Deck Problems: Some owners have faced challenges with the mower deck, such as poor cutting performance, uneven cutting height, or belt slippage.

Next, read on: Kubota l3301 problems

Final thoughts on Kubota GR2120 problems

Other than John Deere tractors,  Kubota Gr2120 is undoubtedly another mower you may need to consider if looking for a heavy-duty garden mower.

The mower is powered by a 21 hp 3cylinderr diesel engine that greatly enhances its mowing capability.

In addition, it is a 4-wheel drive garden tractor, whose front wheels allow the inside rear wheel to move from 100- 0% drive.

Besides, it comes with a 48 inch mower deck and glide steer that allow you to deploy it anywhere.

Unfortunately, like other mowing machines, it has an array of Kubota gr2120 problems you must learn to deal with if you want to use the machine either as a snow blower or garden mower.