Generator Maintenance

Generator Maintenance is a critical part of owning a generator.

Portable generators are a convenient way to provide backup power for your home or business during an outage, but they require regular maintenance to keep them running safely and reliably.

By following the recommended maintenance schedule and using the included checklists, you can ensure that your generator will be ready to go when needed. And by keeping up with the small tasks like changing the oil and cleaning the air filters, you can help avoid bigger problems down the road.

Read the complete article for more information on how to properly maintain your portable generator!

A Guide To Portable Generator Maintenance

Maintenance of any equipment may be defined as carrying out a set of different activities with the aim to

  • assess the general condition by inspection,
  • carry out general cleaning, level checks, adding lubricants, etc
  • measure certain parameters and test the subassemblies to confirm their healthiness,
  • replace certain parts and components after they have been in operation for a certain time,
  • carry out adjustment, modification, or replacement of parts not performing as per the requirement.

Why should you maintain your generators?

Like any other equipment, failure in regularly maintaining your generator will lead to undesirable consequences like

  1. Failure to start during a power outage.
  2. If you are using your generator at a construction site, it could cause excessive downtimes, which may be costly and unproductive.
  3. They can themselves become a safety concern for personnel operating them or lead to scenarios like no lights, no emergency signaling, no power for critical equipment at construction sites, etc.
  4. Reduced lifespan.
  5. Impact warranties from the supplier.

On the other hand, regular maintenance can save you money on parts and repairs and ensure trouble-free operation with a longer life span of the equipment and its availability when you need it most.

While this article is specific to portable generators, we shall be covering the requirements for a standby generator in a separate article.

Types of Maintenance

Maintenance is usually classified into the following four types.

  1. Preventive or routine maintenance – This is implemented on a fixed schedule basis and includes activities like cleaning, washing, replacing, and inspecting to identify existing issues and prevent possible issues through regular care.
  2. Corrective maintenance is unavoidable when routine maintenance or condition monitoring system highlights any major issue or the equipment breaks down.
  3. Predictive maintenance uses a variety of tests to determine the need and time to carry it out.
  4. Breakdown maintenance – These parts or equipment are not maintained regularly as they are low-cost with no major implications on productivity or safety. However, routine maintenance is more expensive than their cost. Hence these are replaced once they fail.

The first two types – preventive and corrective maintenance, are relevant for small generators.

Maintenance Schedules

It is recommended to start preventive maintenance right from the time you purchase a new generator. The owner’s manual provides detailed guidelines and checklists for the machine. If you use your machine more frequently with sustained high loads or use it in a dusty or dirty environment with high temperatures, it is better to increase the frequency further.

The frequency of recommended schedules in most owner’s manuals are

  1. After the first five hours of use,
  2. After each use,
  3. Every 25 hours or every season, depending on the usage,
  4. Every hundred hours or every season,
  5. End of season or annual maintenance.

Maintenance Tools and Kits.

A combination of general purpose tools, small engine tools, greasers and cleaners, supplies, and purpose-made maintenance kits will help you in your endeavor to successfully maintain your generator sets in good order. These items include:

  1. Tools for small engines like spark tester, spark plug gauge, feeler gauges, tachometer, ratchet torque wrench, oil evacuation pump, multimeter, etc
  2. General-purpose tools like socket sets, standard screwdrivers, Phillips screwdrivers, cleaning brushes, power drills, needle nose pliers, standard pliers, adjustable pliers, flat files, adjustable wrench, combination pliers, wire cutters, etc.
  3. Specialty tools if you are experienced in similar tasks or are a DIY enthusiast.
  4. Supplies – Using lubricants and cleaners recommended by the manufacturer for your small engines is always better. These are made for specific tasks and work best in their intended physical and chemical environment. Some manufacturers even go to the extent of formulating the so-called maintenance kits that carry the commonly required spare parts and tools like air filters, spark plugs, engine oil, etc. These kits are of various types intended to carry out different types of maintenance.

Safe Servicing of Generators

Observing certain precautions and relevant safety considerations is important before involving yourself in maintenance or repair work.

Safety Items related to Gasoline Generators

To minimize the fire hazards, observe the following. Some of the items may also be relevant for the generators’ operation.

  1. Avoid using power tools in the vicinity of the generator, as the spark produced is dangerous in the presence of fuel vapors.
  2. Keep gasoline, lubricants, solvents, and other flammable liquids out of reach of the children and in specific UL-approved non-spill-type containers.
  3. The engine must be allowed to cool down before removing the fuel cap or attempting any refueling.
  4. Needless to say, using a matchstick is a strict “NO.”

Safety Considerations for Maintenance

  1. Ensure adequate workspace and easy access to all the tools and supplies.
  2. Always use the correct tools for any job.
  3. Ensure the availability of a fire extinguisher in a known location near the work area.
  4. Family with emergency and engine shutdown procedures.
  5. Disengage the spark plug to prevent accidental starting. Remove the negative terminal of the battery while working on the starter motor. Attach the spark plug and tester back before cranking the engine.
  6. Be cautious before touching cooling fins, cylinder heads, and mufflers as they may be hot.
  7. Ensure that the air cleaner assembly and the blower housing have been fixed back before starting the engine.
  8. Do not transport the engine without ensuring an empty fuel tank and closed fuel valve.
  9. Never increase the speed limits above the prescribed values.

Generator Maintenance Checklists

Please go through the owner’s manual of your generator for the checklist and the generator maintenance tips provided by the manufacturer. It is important to understand that the guidelines in the manuals are based on general experience with the machines on a moderate usage basis and should be carried out at a minimum.

However, you may have to alter the frequency, generally upwards, based on your own usage pattern in terms of the load imposed, hours, observed conditions, and environmental or general factors. Maintaining detailed maintenance logs of all the services carried out on your generator is advisable and recommended.

Check, Inspect, Clean, Change, Adjust, and Test

If you observe the checklists, you will find that the majority of the items can be classified into a few actions like Check, Inspect, Clean, Change, Adjust and Test. These items include:


  1. Check the oil level, fuel level, and coolant (if applicable).
  2. Check the electrolyte level in the batteries.
  3. Check the batteries, battery charger, and associated cables.
  4. Check the air intake system for leaks, loose connections or gaskets, air filter condition, debris around cylinder cooling fins, etc.
  5. Check Engine Compression.
  6. Check the engine mounting bolts.
  7. Check the valve clearances.
  8. Check the idle speed.


  1. Inspect the fuel system, tank, and lines for any leaks.
  2. Inspect the fuel tank for any debris.
  3. Inspect the rewind rope for any signs of wear.
  4. Inspect the exhaust system for leaks, restrictions, muffler, associated pipes, etc.
  5. Inspect the governor springs and associated linkages.
  6. Inspect the ignition system and associated wiring system.
  7. Inspect the circuit breaker and transfer switch.


  1. Clean the fuel tank, line, and fuel filter.
  2. Clean the cooling fins on the engine block.
  3. Clean the spark plug and spark arrestor.
  4. Clean the sediment cup.
  5. Clean carburetor system.
  6. Clean the combustion chamber
  7. Clean the debris from the blower housing.

Change / Replace

  1. Change the engine oil.
  2. Change the oil filters and fuel filters.
  3. Replace the spark plug.
  4. Change any worn-out parts on the unit.


  1. Adjust the spark plug.
  2. Adjusting the idle speed of the generator system.
  3. Adjusting the valve clearances.
  4. Adjust the carburetor.


Testing-related items are more common as part of the troubleshooting exercise. However, carrying out inspection and/or multimeter tests for electrical items like capacitors, windings, carbon brushes, etc., is always beneficial. In addition, test the functionality of the control panels, AVR, GFCI outlets, etc. Make it a point to go through the maintenance requirements of CO sensors in your O & M manual and follow them strictly, as this is a life-saving element.

Additional Items for Natural Gas, Diesel, and Propane Generators

If you are using natural gas, diesel, or propane as your generator fuel, there are certain additional items that you need to carry out in your maintenance schedules.

Natural gas and Propane

  1. It is of prime importance to check for any cracks or leaks in the pipelines and hoses.
  2. Inspect all the associated walls and fittings.
  3. Check and ensure the fuel pressure is at current levels.
  4. In addition, check the tank pressure level for propane.


  1. Check for any accumulated water in the tank.
  2. Ensure that you are storing fresh oil or that necessary stabilizers have been added.
  3. Take the sample from the bottom of the fuel tank and check for any deposits.

End of Season or Annual Maintenance

Engines that are continuously pressed into service performed much better than many small engines used occasionally during power outages and idle most times. Long-term storage has its own drawbacks and results in many unexpected problems in your machines. For example,

  1. Unstabilized gas left in the fuel tank and carburetor can cause varnish and gum formation.
  2. Corrosion can occur in unlubricated parts.
  3. Accumulation of moisture in the ignition system.

While the manufacturers indicate the number of hours of operation before a particular maintenance activity is undertaken. If you are losing your generator sparingly and plan to store it for about 45 days, treat it like this end-of-season maintenance to ensure proper storage. The items include:

  1. Drain the gasoline or any other fuel or add a fuel stabilizer. Drain the carburetor bowl as well and close the fuel valve. We have covered the problems that arise as a result of stored fuel in complete detail in our article on “How To Clean A Carburetor On A Generator?
  2. Change the engine oil. This prevents oil dust particles from sticking to the engine parts.
  3. Seal the fuel cap. During storage, the fuel evaporates into the atmosphere leading to evaporative emissions. Cover the vented fuel cap with aluminum foil and secure it with a rubber band.
  4. Lubricate internal parts. Inject a small quantity of oil to lubricate the cylinder and slowly pull the rewind rope a few times.
  5. Inspect the spark plug. Clean, adjust the gap or replace if necessary.
  6. Service the air cleaner.
  7. Seal the combustion chamber. Take the piston to the top dead center position. The intake and exhaust valves close in this position, not allowing any fuel intake and consequential varnish formation.
  8. Clean and cover the generator set. Do a thorough cleaning of cylinder head fins, areas below the blower housing, and around the muffler. The debris accumulated in these areas can fall into the engine. Then, cover the generator with a plastic sheet and place it in a dry, rodent-free area.


Portable generators are a great backup plan for when the power goes out, but they need to be properly maintained to run safely and effectively. We’ve outlined a guide to generator maintenance and some of the most common maintenance tasks that need to be performed.

Be sure to check your generator’s owner’s manual for specific instructions on how to maintain your particular model. Please let us know in the comments section below if you have any questions or concerns about maintaining your generator.

1 thought on “Generator Maintenance”

  1. Thank you for the suggestion that changing the engine oil occasionally would help to prolong the life of your generator by preventing oil dust particles from adhering to the engine components. Given the unstable electricity in her neighborhood, my sister has been preparing to purchase one for her home. I’ll be sure to let her know about this and look for experts that could assist her with maintaining the generator unit.


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