Hitachi EX120-2 Fuel Filters and Their Importance

[MikePhua]

The Hitachi EX120-2 is a robust and reliable excavator commonly used in construction, excavation, and heavy lifting tasks. As with all machinery, the fuel system plays a crucial role in maintaining optimal performance, and one key component of this system is the fuel filter. The fuel filter ensures that the engine receives clean fuel, free from contaminants that could harm internal components, reduce efficiency, and ultimately lead to costly repairs. In this article, we will delve into the significance of fuel filters in the Hitachi EX120-2, the types of filters it uses, how to identify the right replacement, and the maintenance required to ensure the longevity of your equipment.
Understanding Fuel Filters in the Hitachi EX120-2
Fuel filters are designed to protect the engine by filtering out impurities such as dirt, rust, and water from the fuel before it enters the combustion chamber. The Hitachi EX120-2, like many other heavy-duty machines, relies on its fuel filter to prevent contaminants from damaging critical components, such as the fuel injectors and pump.
There are typically two main types of fuel filters in the EX120-2:

1. Primary Fuel Filter:
   The primary filter is responsible for filtering out larger particles and debris from the fuel. It is the first line of defense and helps prevent the bulk of contaminants from reaching the engine. This filter generally has a larger mesh and can handle more substantial particles like dirt and dust.
   
2. Secondary Fuel Filter:
   The secondary filter provides an additional level of filtration and is often finer than the primary filter. It removes smaller particles that might have passed through the primary filter, ensuring that the fuel entering the engine is as clean as possible. This filter is essential for protecting delicate engine components, such as injectors, from damage caused by fine particles.
   

Both filters are essential for maintaining optimal engine performance. Over time, fuel filters can become clogged or contaminated, leading to poor engine performance, hard starting, or even engine failure if not replaced in a timely manner.
Symptoms of Clogged or Dirty Fuel Filters
There are several signs that indicate the fuel filters in your Hitachi EX120-2 may need replacement:

1. Hard Starting or Engine Stalling:
   A clogged fuel filter restricts the flow of fuel to the engine, which can make it harder for the engine to start or cause it to stall after starting.
   
2. Reduced Engine Power:
   When the fuel filter becomes blocked, the engine may not receive enough fuel, leading to reduced power and performance. You may notice sluggish movement or difficulty lifting heavy loads.
   
3. Increased Exhaust Smoke:
   A blocked fuel filter can cause incomplete combustion, which may lead to excessive smoke from the exhaust. This can also result in increased emissions, which is a sign that the engine is not running efficiently.
   
4. Fuel Leaks:
   If the filter is damaged or improperly installed, you might notice fuel leaking around the filter housing. This is a serious safety concern and should be addressed immediately.
   
5. Engine Misfire:
   An engine misfire, where the engine jerks or runs unevenly, can occur when the fuel supply is interrupted or inconsistent due to a clogged filter.
   

Choosing the Right Fuel Filters for the Hitachi EX120-2
When replacing the fuel filters in the Hitachi EX120-2, it's crucial to select the correct parts to maintain the performance of the machine. Using the wrong fuel filter can lead to poor filtration, leaks, or failure to properly protect the engine.
Here’s how you can ensure you choose the right filters:

1. Consult the Operator’s Manual:
   The operator's manual for the EX120-2 will specify the correct part numbers for the primary and secondary fuel filters. This ensures that you select filters that are compatible with the fuel system of your machine.
   
2. Verify the Engine Serial Number:
   The serial number of your engine can also provide critical information about the correct filter size and specifications. The serial number can typically be found on a metal plate attached to the engine block. This will allow you to confirm the correct fuel filter part numbers.
   
3. OEM vs. Aftermarket Filters:
   While OEM (Original Equipment Manufacturer) filters are recommended for their compatibility and quality, aftermarket filters can offer cost-effective alternatives. However, if you choose aftermarket filters, ensure they meet or exceed the specifications of the OEM filters to avoid damaging your equipment.
   
4. Check Filter Specifications:
   When purchasing replacement filters, check the filter specifications, including the micron rating (which indicates the size of particles the filter can remove) and the flow rate. The EX120-2 typically uses filters that can handle particles as small as 5 microns, ensuring that fine contaminants are captured before they can damage the engine.
   

Replacing the Fuel Filters on the Hitachi EX120-2
Replacing the fuel filters on the EX120-2 is a relatively simple process, but it should be done with care to avoid damaging the fuel system. Here are the general steps for replacing the filters:

1. Locate the Fuel Filters:
   The primary and secondary fuel filters are typically located near the fuel tank and engine. Consult the operator’s manual for the exact location on your model.
   
2. Shut Down the Machine:
   Always ensure the engine is turned off and the machine is in a safe and stable position before starting the replacement process. It’s also advisable to allow the engine to cool down to avoid burns or injuries.
   
3. Remove the Old Filters:
   Carefully remove the old filters by unscrewing them from their mounts. You may need a wrench or filter removal tool to loosen the filters. Be sure to catch any excess fuel that may spill out during the removal process.
   
4. Install the New Filters:
   Install the new filters by screwing them into place. Be sure to follow the manufacturer’s instructions for proper installation, ensuring that the filters are secured tightly and correctly aligned. Make sure the seals are properly fitted to avoid any leaks.
   
5. Prime the Fuel System:
   After installing the new filters, prime the fuel system to remove any air bubbles and ensure a steady flow of fuel. This may involve turning the engine on for a few seconds without starting it, allowing the fuel system to self-prime.
   
6. Check for Leaks:
   Once the new filters are installed, check the filter housing for any signs of fuel leakage. If you notice any leaks, tighten the filter or recheck the seals to ensure everything is properly installed.
   
7. Test the Engine:
   Start the engine and monitor it for any unusual behavior, such as rough idling or smoke. If the engine runs smoothly, the replacement was successful.
   

Maintenance Tips for Fuel Filters
Proper maintenance of the fuel filters is essential for ensuring the longevity and efficiency of the Hitachi EX120-2. Here are some maintenance tips to follow:

1. Regular Inspection:
   Check the fuel filters periodically for signs of damage or clogging. If you notice any issues, replace the filters immediately to prevent further damage to the engine.
   
2. Use Clean Fuel:
   Contaminated fuel is one of the primary causes of clogged filters. Always use high-quality, clean fuel and keep the fuel tank free from debris and water.
   
3. Follow Manufacturer’s Maintenance Schedule:
   Refer to the operator’s manual for the recommended filter replacement intervals. While filters can last for a significant period, replacing them at regular intervals will help maintain the efficiency of the engine.
   
4. Install Pre-Filters if Necessary:
   In some environments, such as dusty or muddy work sites, installing additional pre-filters can help protect the primary and secondary filters from premature clogging. This can extend the lifespan of the filters and reduce maintenance costs.
   

Conclusion
The fuel filters in the Hitachi EX120-2 excavator play a critical role in ensuring that the engine operates smoothly and efficiently by filtering out contaminants from the fuel. Regularly replacing the fuel filters and using the correct parts will help maintain engine performance, prevent costly repairs, and ensure that the machine runs optimally. By following the recommended maintenance procedures, consulting the operator’s manual, and using quality filters, you can extend the lifespan of your Hitachi EX120-2 and keep it performing at its best.