6 Most Common Kubota B3350 Problems

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By Marvin Tucker

Farming Equipment

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Kubota is a name that carries a lot of weight behind it. The Kubota b3350 is well known for its robust mechanical construction and easy handling of extensive farming or agricultural jobs, thanks to its hefty 38hp engine.

But the Kubota b3350 does, unfortunately, suffer from some problems and issues that may not occur immediately. Still, users have reported that by the 100-hour usage mark, some problems and issues have started to crop up.

So today, we’ll take an in-depth look at the most common problems with the b3350 and how you can fix them. As well as discuss whether this machine is worth your money once these issues are factored in.

The most common problems with the Kubota b3350

The b3350 seems like the ideal choice for homeowners with substantial plots of land or for people needing to do small-scale commercial work. It’s excellent at working through challenging and uneven terrain.

It even has excellent emissions control thanks to the tractor’s regeneration capabilities, making it safe for your pets/kids to be in the vicinity, even if you work for prolonged periods.

Let’s look at all the common problems you, as a Kubota tractor/lawn mower homeowner, will face if you purchase one of these units.

1. Regeneration problems and issues

Regeneration is a fantastic modern technology that allows the engine to oxidize accumulated waste soot and particulate from a filter called the diesel particulate filter, or DPF for short.

This allows the tractor/lawn mower to run with a considerably lower emissions output, even when used for prolonged periods.

Unfortunately, the system is not entirely flawless. To first understand the issues that occur here, we need to clarify what active and passive regeneration is:

Passive regeneration occurs as the machine is running. The previously mentioned diesel particulate filter cleans itself by oxidizing the emissions. Once you stop the machine, this process will stop automatically.

Active regeneration occurs when you have stopped the machine if the filter’s particulate buildup has reached a certain threshold (usually around 77%) and the passive cleaning process is not adequately lowering emissions.

In this case, the regen light will pop up when you are parked, warning you that you should permit active regeneration. 

These processes rely on sensors to detect when these processes need to take place. Sometimes these components can fail, causing unwanted and confusing behavior within the regeneration system.

A worryingly large number of b3350 owners have reported this is a prevalent issue. As much as we can suggest solutions here, this seems to be a fundamental manufacturing issue with the model. As such, there is a possibility you will not be able to troubleshoot it yourself.

Sometimes just continuing to drive and use the machine will allow the passive regeneration to lower the DPF content enough to where the system won’t be engaged.

But in some scenarios, you may need to add an additional additive to clean the DPF filter. This way, if the passive regeneration process is not adequate, this can help to alleviate potential blockages allowing natural use of the machine to be enough to keep on top of things.

One final thing to note is if your oil level is too lower (below ¼ of the tank), the vehicle cannot regenerate, so if you are getting a warning like the passive regeneration is not operating, check the oil before anything else!

Knowing the history of this model and the sheer volume of owners who have reported problems, if these suggested solutions do not work for you, then we advise heading straight to the dealer for further clarification. The regeneration system can be pretty complicated and may be well out of the realm of ‘user serviceable.’ 

2. Problems with the electrical system

Unfortunately, this is a universal issue that most tractor owners will need to deal with at some point. Fortunately, the most common problems you will face on the b3350 are pretty easy to diagnose and fix.

If your tractor will not start or is losing power, the first thing to look at is the battery. It may just need charging if it’s spent a significant amount of time in storage or idle.

But if it has been recently charged but seems to shut down significantly quickly, it may indicate an issue with the battery’s ability to hold a charge, so it will simply need to be replaced.

Before you do that, though, check all the electrical connections around the battery, ensure they are solidly connected, and nothing has worked itself loose. You should also check for corrosion or wear that may interfere with any connections and repair accordingly.

Introducing a comprehensive check of all the electrical connections into your scheduled maintenance routine will help you keep up with this.

3. Problems with the b3350 engine

If you find that the engine is not starting, one of the most common points of failure is the spark plug. This small device starts the engine by producing a small electrical spark that ignites the fuel.

It can be a common point of failure due to things like corrosion or dirt and needs to be replaced. Fortunately, spark plugs are inexpensive to replace and relatively easy to install. So don’t mess around here and throw a new one in.

If the spark plug is working, you may find that the engine might not start during the winter months or will struggle for a bit due to the zero-turn operation, which is best suited for warmer months. Don’t be afraid to idle the engine for a few minutes to let things warm up before heading into your heavy workloads to avoid sudden shutdowns and stalls.

The final issue that can occur is with the carburetors. These can become clogged or may need repairing as they adversely affect the engine’s performance when left alone for prolonged periods.

4. The tractor keeps stalling

Sometimes the engine will start up just fine, but after a few minutes of use, the engine will suddenly stall for seemingly no apparent reason.

Providing the regen light is not flashing, another issue is usually at play here.

The most common issue is related to fuel flow issues. For the engine to run smoothly, it requires a consistent fuel flow. If the oil lines become clogged, it can manifest as engine stalls.

Here you should check the fuel system, especially if you see thick particulate or ‘muddy’ textures in the fuel filter. This means the fuel is either old or contaminated. This should be discarded, the fuel system should be flushed, and new fresh fuel should be put in.

You may also find a lack of airflow causes this. When the air filter is blocked by debris, it may restrict the amount of air making its way to the engine, once again causing it to stall. Be sure to clean the filters regularly or replace them as necessary.

5. The cut quality decreases

This is something that a good maintenance routine will allow you to keep on top of.

You may notice that over prolonged periods that the b3350, when used for mowing, has its cut quality degraded over time.

Two primary issues will cause this. The first is that there is uneven tire pressure causing the chassis to lean down on a particular corner. This makes the blades not even across the ground resulting in a jagged cut.

To circumvent this, ensure equal tire pressure across all four tires.

The second issue you will encounter is that the blades will dull over time. The Kubota tractor corporation themselves recommend that the blades be sharpened every six months (for average use loads, if you seldom use the blades, you can get away with once a year).

While doing this, inspect the blades for any significant gouges or chunks that may have been taken out of the blades by something like a rock, these larger dents might not be possible to sharpen out, and the blades might need to be replaced.

6. Software system updates

As tractor technology progresses, digital systems are given more and more responsibility to handle tasks that the user previously handled. The comfort level and ease of use of tractors are at an all-time high.

By and large, the digital aspects of tractors are a great thing, but they do run into some issues from time to time.

If you bought your b3350 some time ago, it would have shipped with the original firmware. Over time Kubota takes feedback from users who report various issues, bugs, and glitches within the tractor’s software.

If yours isn’t up to date and you are experiencing common bugs or glitches, such as rendering the DPF unremovable, then you can try to update the tractor’s software to the latest version.

Kubota b3350 problems: Are they a deal-breaker?

Generally speaking, Kubota tractors receive favorable reviews and are known for their manufacturing quality.

However, when you dig deeper specifically into the b3350 model you will see a worryingly large number of users who have encountered regeneration failing problems, quite literally disabling the entire tractor.

Some claim that the newer versions of this model have rectified the issue and are performing much better, which is why the Kubota tractor corporation still sells it.

However, just based on the sheer volume of complaints, and many dealers’ unwillingness to assist or recall the model if it’s causing issues for you, we consider this tractor to be a risky investment and would advise against one of Kubota’s newer models in lieu of these problems.

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