8 Most Common Kubota B3350 Problems and Effective Fixes

The Kubota B3350 can perform various tasks, from mowing and tilling to hauling and digging.

This tractor comes with a powerful 33.5 horsepower engine, which provides ample power to tackle tough jobs. Unfortunately, the B3350 isn’t immune to problems. The most common Kubota B3350 problems are poor fuel economy, oil leaks, poor cut quality, problematic software, stalling, electrical issues, regeneration problems, and a problematic engine.

Are you a Kubota B3350 owner? If so, knowing what to expect from your tractor is a good idea. Join us as we look at problems that besiege this tractor model and how to fix them.

Kubota B3350 Regeneration Problems

Regeneration issues are among the leading B3350 Kubota problems. The tractor’s engine has a diesel particulate filter (DPF) for oxidizing and emptying soot and exhaust particles from the system. This process reduces emissions when running the tractor.

Regeneration in this tractor occurs in two ways, passive and active regeneration.

When passive regeneration occurs, DPF burns all the soot to empty the filter. This happens as the tractor runs but stops when you stop the tractor.

Active regeneration occurs when driving the tractor short distances. When the soot level gets between 40% and 45%, the B3350 switches to high exhaust temperatures to burn the soot.

Kubota regen problems can occur if you stop the tractor before active regeneration is over. Incomplete active regeneration cycles make the regen light pop up.

If you continue driving your tractor for short distances, active regeneration cycles fail to complete, and soot reaches around 75%. When soot fails to burn in the DPF, it causes blockage.

Another cause of regen problems is a failed sensor in the engine. The sensor connected to the tractor’s emission system can fail and cause regeneration problems. When the sensor fails, the engine won’t regenerate continuously, leading to soot buildup.

Lastly, a regeneration problem can occur if the oil level in the tank is low.

Effective Fixes:

Kubota regen problems can be complicated, so if you can’t fix them, take your tractor to the dealer. Before doing so, you might want to try the following solutions:

  • If you’re driving shorter distances, slow down to allow for complete regeneration cycles.
  • Add a DPF cleaning additive and drive the tractor for around 20 minutes to unclog the filters.
  • Check the oil level and fill the tank if the oil is low.
  • Take the tractor to a mechanic for diagnosis and fixing. The mechanic can use the DPF delete kit software to force engine regeneration.

Engine Problems

Is your B3350 not starting, slower than expected, or showing poor performance? If so, you could be dealing with engine problems.

The main culprits are damaged or dirty spark plugs and clogged or damaged carburetors. When these engine problems occur, they can compromise output and lead to poor fuel economy.

Effective Fixes:

  • Check for damaged, corroded, or dirty spark plugs. If you see such signs, replace the spark plugs.
  • Inspect the carburetor to see if it’s clogged or damaged. If clogged, scrub the mud or dirt and clean it. If damaged, hire a mechanic to replace the carburetor.

Electrical System Issues

Problems with the electrical system are common in most tractors. If your Kubota B3350 has issues with the electrical system, the engine won’t start. Sometimes, the tractor may lose power while running.

The major culprits to watch out for are the battery and connections. Your Kubota tractor might have a faulty battery, dead battery, loose connections, or damaged wiring.


  • Inspect the battery for low voltage. If dead, recharge it fully.
  • Check if the battery terminals are dirty or corroded. Wipe the dirt or corrosion with baking soda, water, and a clean towel.
  • If the battery is faulty, replace it.
  • Check for loose connections and reconnect them. If you find broken wires, replace them.


Some Kubota B3350 users have dealt with an engine that starts but suddenly stalls after running for a few minutes. This happens without the regen light flashing.

If your Kubota B3350 stalls for no reason, it could mean issues with fuel flow or the air filters. Clogged fuel lines will cause your engine to stall. The problem could also arise from old or contaminated fuel.

If the air filter is blocked, you will experience airflow problems that can cause the engine to stall. Like other Kubota B3350 problems, you can fix stalling problems in your tractor.


  • Check for signs of clogs in the fuel system, especially the fuel line and filter. You can fix this problem with solid airflow. However, if the fuel filter remains clogged or dirty, replace it.
  • Inspect for dirt and debris on the air filter. Dirt and debris clog the air filter and cause airflow problems. Clean the air filters or replace them.
  • If you have old or contaminated fuel, drain the fuel from the system and add new fresh fuel.

Problematic Software

Old Kubota B3350 models came with problematic software. Even after upgrading the original software, users complained about many issues with their tractors.

Sometimes, the software may malfunction when engaging transmission gears or turning on headlights. The software also renders your tractor useless if you extract the DPF. This is because manufacturers didn’t update the software correctly on the engine ECU.

How To Fix:

  • Update the software if you’ve removed the DPF and sensors.
  • Take the tractor to a local dealer to replace the ECM and sensors damaged by the problematic software.

Poor Cut Quality

When looking into Kubota B3350 problems, it’s necessary to consider the cut quality this tractor delivers. If you’ve used your tractor for mowing over prolonged periods, the cut quality tends to decrease. The leading causes of degrading cut quality are dull blades and uneven tire pressure.

Blades get blunt over time. They may also have dents or cracks due to friction with sand or hitting harder objects such as rocks. Uneven tires cause the chassis and the blades to be uneven. This results in rough cuts across your yard.

Effective Fixes:

  • If the blades are dull, sharpen them with a hand file, bench grinder, angle grinder, or rotary tool. Sharpen the blades every six months to get the best quality cut.
  • Replace the blades if they appear worn.
  • Restore the tire pressure balance by inflating or deflating the wheels. Use a gauge to check if the tire pressure is even.

Oil Leak

Engine oil leaks in Kubota B3350 result from worn or faulty seals and gaskets, incorrect oil type, or improperly installed oil filter. If you’re running your tractor, you may notice the smell of burning oil, smoke from the engine, or an overheating engine.


  • Check the seals and gaskets for signs of damage. Replace them if necessary.
  • If you’re using an incorrect oil type, check the type your owner’s manual recommends. Drain the wrong oil from the system and add the recommended oil.
  • Inspect the oil filter to see if it’s installed correctly. If not, put it on the right way.

Poor Fuel Economy

Kubota B3350 is large and features a big engine. The powerful motor produces 33.5 horsepower to tackle uneven terrains and large farms.

The eight-cylinder engine consumes more fuel than many tractors in its class. The tractor’s size and heavy weight also slow it down, resulting in more fuel consumption.

Unfortunately, there’s little you can do to solve this problem. While changing the tractor’s engine can reduce fuel consumption, this complex process can cost you a lot of money. For better results, maintain your tractor to keep it running smoothly.

Is the Kubota B3350 Reliable?

Although Kubota B3350 has several problems, it’s a reliable tractor for your large farm. Like any other farm equipment, enhance your maintenance strategy to keep the B3350 in good condition.

If you encounter the above Kubota B3350 problems, use our tips to fix them. Take your tractor to a professional mechanic if you’re unable to fix it.