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How to bleed a diesel generator

How to bleed a diesel generator

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Diesel generators have become an indispensable source of power in various settings, from construction sites and hospitals to remote locations and emergency backup systems. But it’s bad enough when your generator has trouble starting, or worse, doesn’t start at all. Or it starts but then splutters after a while.

This indicates that it is time to bleed the generator. One crucial aspect of maintaining a diesel generator’s performance is the process known as “bleeding”. It sounds a little technical, but it’s an easy task once you know how to do it.

In this article, BISON will tell you through the process of properly bleeding a diesel generator. We will also explain why bleeding is important to your diesel generator care and maintenance. Understanding this necessary maintenance procedure of “bleeding” will help you keep your generator in top condition, allowing it to provide reliable power when and where it’s needed most.

how-to-bleed-a-diesel-generator

Why do you need to bleed a diesel generator?

Bleeding a diesel generator is the process of removing air that has become trapped in the fuel system. This air, often referred to as an “airlock” can significantly impair the generator’s performance.

The fuel system in a diesel generator is designed to be completely filled with fuel, from the tank to the injectors. Any air in this system can compress, unlike the incompressible diesel fuel, leading to inconsistent fuel delivery and potential engine problems. Sometimes, air enters a diesel engine through other channels, such as leaks. Air trapped in the fuel system can cause a range of problems, from poor performance to complete failure to start – This is why you need to bleed the generator. Bleeding the system ensures that all air is purged, allowing for proper fuel flow and optimal engine performance.

Symptoms of a diesel generator needing to be bled

Recognizing the signs of air in the fuel system is crucial for timely intervention. The following are common symptoms summarized by BISON:

  • Engine stalling: In severe cases, air pockets can cause the engine to stall completely.
  • Hard starting: The engine may crank but fail to start, or require multiple attempts to start.
  • Loss of power: The generator is delivering less than its full-rated power.
  • Engine surging: The generator may run unevenly, with noticeable fluctuations in power output.
  • Excessive exhaust smoke: It may be that air in the fuel system is causing incomplete combustion.
  • Unusual noises: Air in the fuel system can cause knocking or rattling sounds as it passes through the engine.

Steps before bleeding the diesel generator

Before fully understanding how to bleed a diesel generator, it’s crucial to make adequate preparations. You need to take these steps:

1.Prepare the necessary tools and materials

wrenches, clean fuel container, clean rags, flashlight, safety goggles, work gloves, owner’s manual, waste container for fuel drips, etc.

2.Safety precautions

  • Well-ventilated area and a fire extinguisher nearby
  • Shut down the diesel. generator, disconnect the power supply, and let the generator cool down.

3.Be familiar with the various components of the generator fuel system

For example, common bleeding points: primary fuel filter, secondary fuel filter, fuel pump, injection pump, individual injectors (some models).

How to bleed a diesel generator

Let’s start bleeding the diesel generator! BISON believes that bleeding operations can be performed effectively as long as the following steps are followed carefully.

1. Identify the leak

If your diesel generator has not been dried, had its filters replaced, or primed before proper use, now is the time to find the leak. Check the fuel lines to see no apparent leakage at the connections. Dusty or dirty areas may suggest a leak because the dirt will stick to the leaking fuel. Replace any fuel lines as needed. While checking all connections visually and manually, if there are any leaks, bubbles may appear or signs of fuel escaping. If a connection is loose, troubleshoot the problem.

2. Start the system

If your generator is equipped with a fuel lift pump. Locate the pump and operate it to fill the fuel lines. This helps push the fuel through the system, making it easier to bleed the fuel.

3. Perform the systematic bleeding operation

  • Start at the fuel filter: First, get out the rag for later scrubbing. Then, locate the bleed screw on the fuel filter housing. Loosen the bleed screw, 2 or 3 turns should be enough (don’t remove it completely). Operate the lift pump or crank the engine until fuel flows out without air bubbles. Finally, tighten the bleed screw once clear fuel is flowing.
loosen-the-fuel-filter-bleed-screw
  • Move to the injection pump: Locate the bleed screw on the injection pump. Then, repeat the process: loosen the screw, pump/crank until clear fuel flows, and tighten the screw.
  • Bleed individual injectors (if applicable): Some systems require bleeding at each injector. You will need to loosen the fuel line to the injector slightly, then start the engine and wait until the fuel sprays out without bubbles before tightening the fuel line connection. Repeat this for each injector.
  • Start the generator and monitor performance: Once you’ve completed the bleeding process at all points, it’s time to test the system. During system engine operation you can review the above paragraph “Symptoms of a diesel generator needing to be bled” again to determine whether the bleeding was successful.  If the generator fails to start or runs poorly, you may need to repeat the bleeding process, focusing on areas where air might still be trapped. This step is indeed very crucial as it ensures that the generator functions properly without any leaks.

Preventive maintenance of diesel generators

  • Regular filter changes: The fuel filter is essential for the quality of diesel entering the generator. Replace the fuel filter according to the manufacturer’s recommendations. More often the generator is used in dusty conditions.
  • Fuel line Inspection: Regularly check fuel lines for cracks, leaks, or loose connections.
  • Air intake system cleaning: Over time, dirt and blockages can accumulate in the air intake system. Clean the air filter regularly and ensure the air inlets are clean and clear for proper combustion.
  • Proper fuel storage: Store diesel fuel in clean, sealed containers to prevent algae growth and contamination. Use fuel stabilizers for long-term storage.
  • Fuel rotation: Use and replace stored fuel periodically. Clean, undamaged oil helps lubricate the engine and prolong its life.
  • Clean fuel tank: Periodically clean the fuel tank to remove sediment and prevent clogging.
  • Run the generator regularly, even if not needed, to prevent fuel system issues.

Regular maintenance is key to preventing air locks and other issues in diesel generators. By following these tips, you can significantly reduce the likelihood of future problems.

Conclusion

BISON cannot overstate the importance of proper bleeding techniques for diesel generators. This crucial process, when done correctly, ensures smooth operation and prevents a host of potential issues. However, bleeding is just one aspect of generator care. BISON would like to emphasize that regular maintenance is absolutely vital for the longevity and reliability of your diesel generator.

For those in need of high-quality diesel generators or other generators, look no further than BISON. As a leading generator supplier in China, BISON’s commitment to excellence extends beyond the point of sale, ensuring that you have expert support throughout the lifecycle of your generator. By choosing BISON, you’re not just purchasing a generator – you’re investing in peace of mind for yourself and your customers.

FAQs about making your generator quiet

A diesel generator is like any other diesel engine in that it should not be run dry, i.e., running it already in the cylinders without fuel, as this can cause severe damage. To prevent it from drying out, the diesel engine should be drained before its first use, when it has been repaired, when filters have been changed or tinkered with, or if it has run out of fuel. Therefore, it should be primed to avoid filling air where fuel should be added.

  • Routine maintenance: During operations such as changing fuel filters or servicing fuel lines.
  • Extended periods of disuse: If a generator sits idle for a long time, especially in fluctuating temperatures.
  • Loose connections: If the fuel line connections are not tightened properly or are worn.
  • Running out of fuel: If the generator runs out of fuel, air is drawn into the fuel lines as the engine tries to draw from an empty tank.
  • Fuel filter replacement: Fuel filter changes often introduce air into the system, especially if not done carefully.

While many maintenance tasks can be performed by owners, some situations require professional assistance:

  • Major fuel system repairs
  • Engine overhaul or internal repairs
  • When troubleshooting steps don’t solve the problem
  • If you’re unsure about a procedure or don’t have the necessary tools

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