9 Common Kubota GR2120 Problems and Solutions

Kubota GR2120 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.

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.

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.


  • 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.

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.

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.


  • 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.


  • 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.


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 to offer maneuverability. Here more on kubota lawn mower 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 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.


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.