Generator Maintenance and Service: All You Need to Know!

Generators are always there to keep you connected to the world when there is a power outage. For whatever reason you’re using the generator for, be it emergency or primary power source, you must give it periodic maintenance and service. A generator is a machine with no self-maintenance system. That means it relies on your efforts to maintain it, and in return, it gives you optimal performance.

Creating a planned maintenance schedule and carrying out all associated testing ensures generator availability when you need it most. And you know what, the possibilities of a generator failure double when generator maintenance and service checks are not performed right. If possible, you need to carry out routine-planned preventive maintenance and service.

What’s Preventive maintenance and service (PMS)?

Preventive maintenance and service, PMS, is a typically done maintenance schedule based upon the engine hours and periods. The cycle must be adopted to meet specific generator application needs. The more hours in a year your generator operates, the more frequent you need to service it. Your generator’s environment also plays a role. If you place it in a more severe climate, somewhere dusty, extremely cold or hot, highly humid, etc., the servicing needs to be more frequent.

The Concept of Planned Maintenance in Generators

One way of administering generator maintenance and servicing is by planned maintenance method. It can be defined as maintenance, performing service, inspections, and testing of your generator on a pre-determined schedule. Every maintenance stage must include the following status inspection:

Calendar Cycle Schedule

The calendar cycle schedule requirements can be done weekly, monthly, quarterly, semi-annually, and annually, depending on the generator manufacturer’s recommendation and application.

Operating Inspections

Most of these inspections are done when the generator is operating. You can only monitor critical operations during 100% of running time. The non-critical functions, on the other hand, have checks done as determined by the generator application.


If your generator is no longer in active use, you have to place it in a layup. The layup procedure may include disconnecting the generator batteries, draining its fuel system and changing the fuel filters, and draining the coolant and changing coolant filters. There is also replacing the air filters, covering all intake and exhaust ports, and disconnecting all generator supply connections.

Standby Generator Maintenance & Service Tips

Standby generators are the most forgotten generator units when it comes to maintenance. Why? A standby generator runs by itself. It will start up by itself when it detects power loss and shuts itself down when the main power is restored. That means you will probably check it out when refilling it if it’s a diesel generator or if it runs on limited propane or natural gas supply.

However, if the unit is connected to an unlimited gas supply, you might forget to attend to it. That’s why an ideal maintenance method for standby generators is the Preventive Maintenance and Service. Here is the few PMS procedure you can perform to your standby generator to maintain optimal performance and readiness.

Generator Cleaning

After some time, standby generators collect dust, which becomes sticky grime when mixed with grease, oil, and fuel spill residue. If not cleaned, it might give you a hard time finding leaks later. You should clean it from time to time with rags and a degreaser.

Gas Tank Check

One disadvantage of gasoline or diesel is a short storage time. When stored for an extended period, it can gum up inside the fuel filter, carburettor, fuel lines, etc. If your standby generator hasn’t been operational for a while and there is old fuel in it, you should check the user manual for the manufacturer’s recommended action.

Some generators require draining the old fuel and priming them with new. Some manufacturers recommend a complete generator service that includes replacing the old lines and filters and cleaning the fuel tank and carburetor.

Engine Check

Another crucial generator maintenance to give to your standby unit is engine check. You need to monitor the fluid levels, the oil pressure, and the coolant temperatures more frequently. Most of the modern generator’s engine gives warning early.

So, watch and listen for any changes with engine performance, appearance, and sound that indicates a service or repair is required. It can be misfires, excessive vibration or exhaust smoke, increased oil or fuel consumption, or loss of power.

Any of the symptoms would mean you need to call a generator maintenance and service repair company to restore the operational engine state.

Oil Change

A yearly oil change is essential no matter the number of hours you have used your standby generator. Changing the oil is a simple DIY process. The first step is to run the generator for a few minutes to warm the engine. That helps the oil and its contaminants to drain smoothly. Next, place an oil catcher under the generator’s oil pan and open the cap.

Once the oil drains completely, replace the oil cap while you also change the oil filter. When done, you can now fill the generator engine with the manufacturer’s recommended oil and rerun your generator. That allows the oil to reach all the corners of the generator engine. After it runs for a few minutes, please turn off the generator, and recheck the oil level to make sure it’s ideal.

Air Filter Check

You must also check the air filters and change them if necessary. Air filters vary depending on the engine type. Some use rings with no center, some use rings with a center, and some use flat designed filters.

The frequency of changing the air filter depends on the generator type and the operational hours. In general, you’re required to change the air filter element in the first 250-hours of operation and 500 hours of each operation after that.

Check your generator’s manual for instructions on how to change the air filter. Changing it is often easy as all you need is to unscrew the old one, apply some oil to the new filter gasket and screw it.

Spark Plugs Check

A faulty spark plug would mean your generator won’t start. It’s necessary to start the fire that burns the fuel inside the engine. It needs regular servicing to keep it clean and in shape. How do you inspect it?

Start by disconnecting the spark plug wire and clean around it to prevent debris from falling inside once you remove it. Use a spark plug socket, mostly provided with the generator, to remove the old spark plug. Use a spark plug cleaner and wire brush to clean it.

If you notice persistent deposits or cracks in its porcelain, you’ve to replace it. While replacing it, adjust the new spark plug electrodes gap using a spark plug gauge to the manufacturer’s specs. When done changing the hole, you can now replace it and reattach the wire.

Fuel Filter Check

After the first 200-hours of operation or 500-hours of each process, you need to change the fuel filter. However, that varies from one generator engine to the other. Checking the fuel filter varies with manufacturer, but most of the inline fuel filters require you to close the fuel valve, open the clamps on each side of the filter and pull it out.

Inspect it by looking through it; try and look for light shining through. If there is no shining light, you have to replace it. Replacing the fuel filter is a reverse of what you just did to remove it. However, do make sure to keep the filter interior clean. If it has an arrow on it, you need to point it to the fuel flow direction.

Battery Checks & Inspection

A weak or undercharged starting battery is a common cause of standby generator start failure. A good battery needs to be fully charged and well-maintained as it helps avoid dwindling. It’s done by testing and inspecting its states regularly. Before anything else, you have to clean the battery terminals. The best way is to use a baking soda solution and water to clean off any corrosion. Next is to use a battery tester for checking the state of your generator battery and replace it if necessary. You also need to check the gravity and electrolyte levels frequently.

Testing batteries

Merely checking the generator battery output voltage does not indicate its ability to deliver adequate starting power. As the battery or batteries age, the internal resistance to its output current flow increases. The only way you can measure the terminals voltage is when under load. For some generator, the indicative battery test is done automatically when the generator starts. For other generators, you have to use a manual battery load tester to inspect the starting battery’s condition.

Cleaning batteries

As aforementioned, the generator starting battery can get dirty. I did mention how to clean. I would love to say; it’s crucial to keep the batteries clean. Wipe them with a damp cloth any time you see dirt appearing excessive. If you notice any corrosion around the terminals, clean them too. Take out the cable and use a baking soda solution (a mixture of 1/4lbs baking soda and 1 quart of water.) Make sure the solution doesn’t enter the battery cells. Flush the baking soda solution with clean water once you’re done. Replace the connection cables and coat the terminals with a light petroleum jelly application.

If your generator is using lead-acid batteries:

Check for specific gravity.

For open-cell lead-acid batteries, you need a battery hydrometer for checking the specific gravity of its electrolyte in each cell. A fully-charged lead-acid battery has a specific gravity of around 1.260. If this value is below 1.215, it’d be best if you charge it.

Check for electrolyte levels.

Another thing to check in open-cell lead-acid battery is the electrolyte level after every 200 hours of operation. If it’s below the mark, fill the battery cells with distilled battery water to the bottom of the filler neck.

Regular Generator Engine Exercise

Another essential generator maintenance and service practice are to exercise the generator engine regularly when storing for a long time. You must run your generator for 30 minutes with a load once a month to avoid staying idle for too long. It helps to ensure oil reaches all the engine parts to prevent rusting and thwarts any electrical contact oxidation. Exercising also helps check and make sure everything is working just fine. Remember to empty the gas once you’re done with the testing just before your store it again.

Exhaust System Check

When you set the generator operating, check the entire exhaust system, including the muffler, exhaust pipe, and exhaust manifold. Look for leaks at all the connections, gaskets, joints, and welds. Make sure the exhaust pipes do not overheat the surrounding areas. If found any leaks, repair them or hire a generator maintenance, service, and repair company for the job.

Leak Check

If you never found any leaks while cleaning the generator, now is an excellent time to check them out. Once the generator is run for exercising, the leaks might present themselves. Run the generator on a clean surface to help identify the leaks. As mentioned above, repair them or hire a generator maintenance, service, and repair company for the job.

Portable Generator Maintenance & Service Tips

Portable generators are the most used generators, especially at home. This is the power horse you would take with you in your RV, camping, or tailgating. And the best part is, you can use it for home emergency power as well. However, like any other machine with a couple of systems and moving parts, it needs maintenance and servicing to ensure it performs optimally. Here are the top maintenance and service tips to give your portable generator:

Fill the tank with fresh fuel.

If you’re using a gasoline or diesel (although rare) portable generator and has been in storage for quite a while now, you should drain all the fuel in it and refill the tank with fresh primed fuel. Remember to also drain the whole fuel line before opening the fuel valve. If the fuel inside the fuel tank is over a year old or contaminated with water and if you never used any fuel stabilizer during storage.

Check and Charge the battery.

If your generator uses an electric start, you must check its electric start battery status to make sure it has charge enough to start the generator. Clean the terminals of any rust by disconnecting the cables, washing them with a small baking soda solution mixed with water, and rinsing with clean water.

If the battery is low in charge, you can use a battery tender to give it enough current to start the generator. The battery has a system that allows charges when the generator is running and stops charging when the cell is full. Remember to monitor the charging and test to see if the battery is charging. If not, or if the charge doesn’t serve its purpose, you’ll need to replace it with a new one.

Replace the Pull Cord

One of the most common problems faced by portable generator owners is a broken pull cord. The good news is, replacing it is relatively easy and quick, even using a flashlight when there is a power outage. Even though replacing it might seem like a simple wind-it-up process, you have to watch out for the spring.

Before wrapping the new pull cord around the starter, ensure the spring is wounded as far as it can go. Forgetting to do this can cause the pull cord to hand from the generator since there is no functional spring to take it back into its housing. It will also start your generator at all. If the pull cord is still intact, inspect for any tear signs; if any, keep your replacement cord near.

Spark Plugs

The generator start might be working right, but the generator is not starting due to a dirty or faulty spark plug. You must give it a cleaning and replacement service whenever necessary. Now and then, remove it and give it an inspection to know its status.

Removing the spark plug is simple and straightforward. All you need is to remove the spark plug wire, clean the debris around it and then remove it from the engine shell. Clean it with a dry cloth. If you notice any cracks or excessive dirt on the porcelain, you need to replace it.

Oil Change

A portable generator engine is its workhorse; it does the hard part of producing power. It needs ideal oil to keep them lubricated and lower wear and tear, with it having multiple moving parts. That’s why you must ensure your generator is running on fresh oil and at the right level. Modern portable generators come with a low-oil shutdown feature that allows you to keep an eye on the amount of oil remaining in the engine. You’re also required to change the oil for at least 50 hours of operation, depending on your generator.

Replace the Fuel Filter

The fuel filter is an essential component in the generator fuel line. It’s put there to filter out dust, debris, and dirt found in fuel from corrupting the energy getting to the engine. With the filters lacking a disposing mechanism, they might get clogged over time after collecting all the dirt and contaminants. If they block, the fuel system will get little to no fuel, and your generator won’t run optimally.

Check for the user manual to know the best time to replace the filters and replace them. You can also try shutting the fuel valve, detaching the fuel line to the carburetor. Place a container or bucket to collect any leftover fuel. Remove the fuel filter and replace it with a new one; you might want to unscrew some screws to get to it.

Unclog the Fuel Lines

Portable generators also suffer fuel line clogging, especially after staying in the storage for a long time without engine exercising. When clogged, it will prevent fuel supply from reaching the generator engine. Fixing the problem is simple; service the fuel line by clearing out debris. That might not be enough or efficient if you have a bigger problem.

If your generator uses a tube delivery system, the fuel line can become cracked or torn with time. If that is the case, it is best to skip the repairs and replace the while line. The replacements are sold in various sizes and available at fair prices.

Clear Blocked Gas Vent

Gas flows smoothly from the gas tank using gravity and air pressure allowed inside the gas tank by the gas vent. It’s a small hole found on the gas cap looking like a valve or a slight hole. When clogged, the required airflow won’t be available, thus cutting off the gas, preventing it from reaching the carburetor. If slightly plugged, the fuel flow will be limited. You must clear it out for the right amount of fuel to reach the engine.

Store It Properly

If you’re not planning on using the generator anytime soon, the past 30 days, it’s necessary to take specific steps to protect your generator’s engine. The first thing you have to take is to conduct all the recommended maintenance and service procedures.

Please remove the battery and clean its terminals. Also, make sure it’s charged fully.

Drain any fuel in the gas tank and inside the carburetor float chamber.

And to prevent the cylinder bore from rusting, remove the spark plugs and inject few oil drops via the plughole.

Pull the recoil starter knob 2-3 times gently before placing back the spark plug until you feel resistance. Please leave it in that position.

Finally, do a general cleaning of the cooling air slots and openings and not be obstructed.

You should also cover your portable generator with an ideal protective generator cover and store it in a dry place.

If you have fuel remaining in the fuel can, you should use a fuel stabilizer to prevent it from going bad.

Always exercise the generator once each month to make sure everything is running right, lubricate all the generator parts, and prevent long-term idling.

Why Is Generator Maintenance & Service Important?

At this point, it’s quite clear that you must give your generator the correct maintenance and services at least once a month, quarterly, semi-annually, or annually. But do you know why you have to do it? If you don’t, let me give you some reasons to perform the above maintenance and servicing procedures.

Keeps the generator ready for next time you need its services

Power outages will never knock on your door to tell you that it will happen. A generator is an emergency power unit designed to come in handy when power loss hits surprisingly. The generator has to stay ready for such an occasion. That’s why you should keep giving it the necessary maintenance and service.

Prevents fuel problems

With proper generator maintenance, you can be sure you won’t be dealing with fuel problems such as clogged injectors, algae build up on the fuel line, and a dead starter battery. These are problems that might ruin even the generator itself if not attended to soon.

Saves you money

It might seem like an expensive thing to do, especially if you have some part needing replacement. What you need to know is, if you ignore to give your generator the right maintenance, you might end up spending more on repairs. You might even be forced to buy a new generator. So, the proper generator maintenance and service will save you money in the long run.

Improves Generator Lifespan

A generator is an expensive investment that you don’t have to make often unless you’re updating the current unit. By giving your generator routine maintenance, you will be allowing your generator to enjoy a smooth run, and in the long run, you will be improving its lifespan.

Final Thoughts!

Giving your generator routine maintenance and service isn’t an option; it’s a MUST. If you want your generator to survive through the storage period and still function right, you must maintain it properly. If you want the generator lifespan to improve, you must give it the proper maintenance. It’s that simple.

About the author

Sharif Miah

I am Sharif, 22, a student, currently doing the BBA program. Besides, I am an online Blogger.

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