Onan Generator Troubleshooting No Spark

To troubleshoot no spark in an onan generator, first check the spark plug and ignition coil. Then, inspect the wiring and fuel system for any issues.

A generator is a vital source of power during blackouts or in remote locations where there is no electricity grid. But when it fails to function properly, it can cause inconvenience and frustration. One of the most common issues with an onan generator is no spark. The generator requires a spark to start, and if there’s none, it won’t turn on. Troubleshooting the issue involves carefully checking the spark plug and ignition coil for any damage or wear and tear.

An inspection of the wiring and fuel system is also necessary to identify any issues that could be contributing to the problem.

Possible Causes Of No Spark

Troubleshooting a no spark issue in an onan generator can be challenging, but knowing the possible causes can make the process easier. A lack of spark means that there is no firing in the spark plug.

Lack Of Fuel Supply

Without fuel, the generator will fail to provide the spark necessary to ignite the engine.

  • Empty fuel tank
  • Clogged fuel filter
  • Malfunctioning fuel pump

Fouled Spark Plug

A spark plug can also cause a lack of spark, and this could be as a result of the following:

  • Dirty spark plug
  • Faulty spark plug
  • Wrong spark plug gap

Defective Ignition Coil

Controlling the spark that ignites the fuel inside the generator engine is the ignition coil. If this coil is defective, it will not be able to generate the electric charge required to start the engine.

  • Disconnected ignition coil wire
  • Faulty ignition coil
  • Ignition coil has grounded off

Malfunctioning Voltage Regulator

The voltage regulator ensures that the voltage output from the generator stays at the required level. However, if it fails, it could lead to no spark or a loss of power in the generator.

  • Burnt-out rectifier
  • Burnt-out field winding
  • Defective voltage regulator

Wiring Issues

Wiring problems can contribute to a no-spark issue in the generator.

  • Poor or damaged connectors
  • Broken wires
  • Short circuit

Troubleshooting a no spark issue in the onan generator can be a complex task. However, it is important to start by eliminating the possible causes. Paying attention to these various problems and fixing them accordingly can alleviate the issue and get your generator running smoothly.

Diagnosing The Problem

Onan Generator Troubleshooting No Spark

When you rely on an onan generator to power your rv or home appliances, it can be frustrating when it won’t start due to a lack of spark. Fortunately, the problem is often easy to diagnose, and you can troubleshoot and fix it without too much hassle.

In this section, we’ll look at the potential reasons you might encounter this issue and the steps you can take to diagnose the problem.

Checking The Fuel Level And Fuel Supply

One of the most common reasons for an onan generator to fail to spark is due to a lack of fuel reaching the engine. Thus, the first step you should take is to ensure that your fuel levels are adequate, and the fuel supply is flowing normally.

Here are some key points to consider:

  • Check and fill the fuel tank if it is empty.
  • Check the fuel filter and replace it if it’s dirty.
  • Inspect the fuel lines to make sure there are no blocks or leaks.

Inspecting The Spark Plug And Replacing If Necessary

The spark plug is responsible for igniting the air-fuel mixture inside the engine’s combustion chamber. If it is malfunctioning, it’s unlikely that the generator will start. Thus, the second step in diagnosing the problem is to check and replace the spark plug if necessary.

Here are some key points to consider:

  • Inspect the spark plug for signs of wear and tear, such as erosion and cracks.
  • Remove the spark plug and clean it with a wire brush.
  • Use a spark plug tester to check for sparks between the electrodes.
  • Replace the spark plug if it is damaged or malfunctioning.

Testing The Ignition Coil With A Multimeter

If the spark plug is in good condition but still not providing spark, the ignition coil may be the issue. The ignition coil delivers power to the spark plug, and if it is faulty, the spark won’t reach the engine.

Therefore, the third step in diagnosing the problem is to test the ignition coil using a multimeter.

Here are some key points to consider:

  • Make sure the ignition switch is off and disconnect the ignition coil.
  • Set the multimeter to the ohms setting and place the leads on the positive and negative terminals of the ignition coil.
  • Inspect the meter reading and compare it to the manufacturer’s specifications.
  • Replace the ignition coil if it is not functioning correctly.

Testing The Voltage Regulator

The voltage regulator is responsible for regulating the voltage output from the generator. If it is malfunctioning, there may be interruptions in the spark flow, causing the generator to fail to start. Therefore, the fourth step in diagnosing the problem is to test the voltage regulator.

Here are some key points to consider:

  • Set the multimeter to the voltage setting and connect it to the battery.
  • Start the generator and measure the voltage output at the battery.
  • Compare the reading to the manufacturer’s specifications.
  • Replace the voltage regulator if it is not functioning correctly.

Checking The Wiring Connections For Any Loose Or Damaged Wires

Loose or damaged wiring connections could cause issues with the flow of spark and prevent the generator from starting. Thus, as a final step, it’s important to check the wiring connections on the generator’s engine.

Here are some key points to consider:

  • Inspect all wiring connections and ensure that all wires are in good condition.
  • Check for loose connections or wires that have come undone.
  • Make sure no wires are melted or otherwise damaged.
  • Secure any loose or damaged connections and replace any faulty wires.

Diagnosing an onan generator that won’t start due to a lack of spark is a straightforward process. By following these steps, you can identify the cause of the issue and fix it without requiring the help of a trained mechanic.

Remember to always prioritize safety when working with electrical components and follow the manufacturer’s instructions carefully.

Fixing The Problem

If your onan generator is not starting or running properly, the issue might be as simple as a failing spark plug or something more severe like a bad ignition coil.

Steps To Replace Or Repair The Faulty Parts

  • The first step is to identify the faulty parts that are causing the generator to malfunction. Conduct a thorough inspection and look for any defects or broken components.
  • Once you have located the faulty parts, you can either repair or replace them, depending on the nature of the damage.
  • If the parts are beyond repair, consider replacing them with high-quality original parts to avoid any future issues.

Cleaning Or Replacing The Spark Plug

  • A spark plug can become dirty or damaged over time, resulting in a loss of spark or misfiring. To fix this issue, remove the spark plug using a socket wrench and inspect it for any signs of wear or damage.
  • If the spark plug is dirty, use a wire brush to remove any debris and clean it thoroughly. If it is damaged, replace it with a new one to restore its capacity to produce a spark.

Repairing Or Replacing The Ignition Coil

  • If the spark plug is not the problem, the issue could be with the ignition coil. The ignition coil is responsible for generating the electrical spark that is needed to ignite the fuel. A faulty ignition coil could cause the generator to misfire or not start at all.
  • To test the ignition coil, use a multimeter to measure the resistance. If the resistance is not within the manufacturer’s specifications, the ignition coil needs to be replaced.
  • If you are unsure about how to test or replace the ignition coil, seek professional help from a trained technician.

Replacing The Voltage Regulator

  • The voltage regulator is another component that can cause a no-spark issue. It regulates the amount of voltage that is supplied from the generator to the equipment being powered. If it is malfunctioning, it can cause a loss of spark or overcharging of the electrical system.
  • To replace the voltage regulator, locate it on the generator and remove the mounting bolts that secure it in place. Disconnect any wiring connections, and replace it with a new voltage regulator that meets the manufacturer’s specifications.

Fixing Any Wiring Issues

  • Wiring issues can also cause a loss of spark in an onan generator. Check for any loose or damaged wiring connections and fix them immediately.
  • Make sure that all wiring is properly connected and secured, and that there are no damaged wires or frayed insulation. Check the wiring diagram in the owner’s manual to confirm that the wiring is in the correct configuration.

By following these steps, you can troubleshoot and fix a no-spark issue in an onan generator and get back to powering your equipment. However, if you are unsure about any of the steps mentioned above, seek professional help from a trained technician to avoid any mistakes and ensure your safety.

Maintenance Tips To Prevent Future Problems

To prevent future problems and ensure your onan generator runs smoothly, it’s important to schedule regular maintenance. Properly maintaining your generator can increase its lifespan, prevent costly repairs, and guarantee that it will function in the event of an emergency power outage.

Neglecting regular maintenance can lead to malfunctions, frequent breakdowns, and even total failure.

Steps To Maintain The Onan Generator

Here are some essential maintenance tips that you should follow for your onan generator to prevent future problems:

Checking And Cleaning The Air Filter

An air filter prevents dirt, debris, and other contaminants from entering the generator’s engine. Over time, the filter becomes clogged and needs to be cleaned or replaced. To clean the air filter, simply use a soft-bristled brush and compressed air to remove any dust or dirt.

If the filter is damaged, it should be replaced to guarantee optimal performance.

Changing The Oil And Oil Filter

Routine oil changes are imperative to keep the generator running smoothly. Old oil can damage engine components and lead to reduced performance. Refer to your generator’s user manual for specific guidelines regarding the recommended oil type and frequency of oil changes.

Also, replace the oil filter at the same time as the oil change to ensure engine longevity.

Monitoring The Fuel Level Regularly

Running your generator with a low fuel level can cause damage to the generator’s engine. This is why it’s essential to monitor the fuel level regularly and fill the tank as needed. Regular inspections of the generator’s fuel system will also help identify any leaks or damage.

By following these maintenance tips, you can keep your onan generator in excellent condition. Regular upkeep and inspections are the best ways to prevent issues and guarantee the generator is ready to power your home or business when required.

FAQ For Onan Generator Troubleshooting No Spark

What Are Some Common Causes Of No Spark In An Onan Generator?

Common causes for no spark in an onan generator include faulty spark plugs, a faulty ignition coil, or a broken flywheel key. Other causes can include a malfunctioning oil level sensor or a faulty spark plug wire. Proper maintenance can help prevent these issues.

How Can I Troubleshoot My Onan Generator If It’S Not Producing A Spark?

To troubleshoot an onan generator that’s not producing a spark, check for fuel and spark issues. First, make sure there’s enough fuel in the tank. Next, check the spark plug to see if it’s corroded or damaged. Replace the spark plug if necessary.

If the generator still doesn’t produce a spark, consult a professional electrician.

What Steps Should I Take To Fix A No Spark Issue With My Onan Generator?

To fix a no spark issue with your onan generator, start by checking the spark plug. If it’s dirty, clean it. If it’s damaged, replace it. Next, check the ignition coil and spark plug wires. If necessary, replace them. Finally, check the voltage regulator and battery, as low voltage can also cause a no spark issue.

Are There Any Specific Parts That Are Commonly Responsible For A No Spark Issue In An Onan Generator?

Common parts that could be responsible for a no spark issue in an onan generator include the ignition coil, spark plug, and the control board. It is important to check these parts for any damages or defects when troubleshooting the issue.

Can I Perform Onan Generator Troubleshooting For No Spark Issue Without Any Tools And Experience?

No, it’s not possible to perform onan generator troubleshooting for a no spark issue without any tools and experience. The process requires a multimeter, spark tester, and technical expertise to identify and fix the problem. Contact a professional technician to help you determine the issue and resolve it.


After going through this comprehensive guide about onan generator troubleshooting, you must now have a better understanding of what could be causing your generator to have no spark. Remember, regular maintenance can go a long way in avoiding these issues.

Make sure to follow safety protocols when troubleshooting and maintenance and always work with a professional if you are not confident in your abilities. Ignoring any issues with your generator could lead to bigger problems and costly repairs in the long run.

Luckily, by following the tips and techniques mentioned in this article, you should be able to successfully identify and fix any no-spark issues in your onan generator.

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