How to maintain a generator


Generators are power equipment used to provide power when and where power is not available.  Maintaining your generator is a key component to make sure the backup power source is always available when called for, either during a power outage, emergency, traveling, or working in a remote area.   

The guidance in this article is for generators, and can also be applied to woodchippers, pressure washers, and other power equipment with small engines.   

What can go wrong?  Typical engine-generator set issues 

Not maintaining your generator can cause the engine to not start, fuel leaks, dead battery, or loss of available output are typical issues from not taking proper care of an engine-generator set.

Let's answer a basic question.  Can the generator get wet? 
Water and electricity are a dangerous combination to people and animals.  So let's examine this danger. 

Generators should never been run indoors, in garages, or anywhere that can allow engine exhaust to build up.  The engine emissions are poisonous to breath, and will cause serious threats to your health, losing consciousness, then eventual death.  In short, the generator needs to be run outdoors over 20 feet away from doors, vents, windows, or crawl spaces. So what happens when it is exposed to the elements such as rain or snow?   

Here is some sound advice, avoid operating the generator in stormy conditions, heavy rain, or snow.  If you do, you can run the risk of someone being electrocuted.    

Whenever possible, it is a good idea to provide a covering for the generator.  Operate the generator under a canopy structure is a wise move, covering the top of the generator from direct exposure.  But know that a canopy covering will not completely block out the rain.  You must also ensure the tarp allows adequate airflow and ventilation.   

If a generator becomes wet, you don't want to let it remain wet for a long period.  Even if it is submerged in water, you can prevent much damage by using a hot blower or placing out in direct sunlight.  Hopefully only the spark plug may need to be checked, but water inside the carburetor will lead to mechanical repair.

Basic Maintenance will ensure long lasting performance. 

So first think about how you treat a car.  You would not let the car stay parked long term in a driveway and expect for it to startup magically after six months of never being turned on.  Most apartments do not allow car storage, because the car will become a dead car when it sits too long, and the only way to move it is with a tow truck.  This is simple engine concepts that it has to run to stay operational.

If you are still reading this, we want you to know that you are on the right track to being a happy generator owner.

How to maintain an engine-generator set   

Generator safety Make sure the power switch is in the "Off" position, and disconnect the spark plug wire before working on the engine to prevent accidental startup.  Guards are in place to protect users from moving mechanical parts, but always use caution to protect people and equipment from unnecessary damage.   

Cleaning the generator 

Like anything you take pride in, you want to keep it clean.  Use a damp cloth to wipe the exterior surfaces clean.  Do not allow dirt to build up on the engine or generator.  Inspect cooling air slots and openings to make sure they are kept clean and unobstructed.  Do not wash with a garden hose or pressure washer to avoid damaging electrical components.     

Change the oil  

Intervals for changing the oil can change according to hours of usage or time in storage.  When changing the oil, first run the generator a few minutes to heat the oil up, which makes it easier to clean.  Then stop the generator and wait unit the engine is cool enough to touch.  Unscrew the oil drain plug and collect the oil.  Oil must be properly disposed of at a recycle center.  Replace the oil drain plug on even ground, and then refill the crankcase with oil to the full line.  Easy.    Most generators will require oil change within the first 30 hours, smaller generators require it sooner.  When refilling the crankcase with oil, be sure not to overfill with oil.

Changing the oil on a generator

Cleaning the air filter 

Unscrew and remove the air filter cover so you can remove the air filter.  Clean the air filter with soapy water, then rinse with clean water.  Squeeze the air filter with a clean cloth, and leave the air filter flat to dry.

Changing the air filter on a generator

Exercise the engine regularly 

Best practice is for each month to keep the generator running for about 30 minutes under a load.  Connect it up to a load with an appliance that uses a motor while running, such as a box fan or heater.  This practice ensures that both the alternator and engine are exercised.  Long periods of running without a load can cause the generator to malfunction.   

If monthly exercise is not possible, at least perform this once every three months with same 30 minute exercise, longer exercise time is not required to maintain unit.  If the generator is unused for 30 days or more, apply fresh oil and commercial oil stabilizer before operating or storing it. 

Charging the battery 

Similar to the engine and alternator, you should charge the battery once a month.  Charge it for one day, but be careful not to overcharge.  All-Power generators can be started manually if the battery does not power the electric start by using the manual recoil start.  Check the terminals for corrosion and clean if necessary with wire brush and check battery.

Fuel Tank 

Never leave your gas tank empty enough to fill with air to prevent rusting and many other issues.  Fill the tank up.  

Fuel Tank Maintenance

Spark Plug Service 

First clean around the spark plug area.  Disconnect the spark plug wire.  Replace the spark plug if electrodes are pitted, burned, or the porcelain is cracked.  Check the gap of the spark plug with a feeler gauge, then install the spark plug and tighten it firmly.  Connect the spark plug wire.

Replacing a Spark Plug Service on a generator

Generator Storage 

When storing the engine-set for long term storage beyond 3 months, be sure to consider removing the spark plug cap, fuel filter replacement, spark arrestor service, and valve adjustment.  Consult a professional as needed.

Long Term Storage 

Long term storage is considered beyond six months of no planned operation.  This will focus on storing 4 Stroke Engines requires straight gasoline only – NO oil mix

1. Remove and dispose of old fuel from the tank.   

2. Add a high octane gasoline (only a small amount) with a fuel stabilizer to your fuel tank. Preferably use a stabilizer with a fuel system cleaner and cylinder lubricant.   

3. Start the engine and allow it to run for 5-10 minutes. This gives the stabilizer time to work through the entire fuel system.   4. Allow the engine to sit for 20-30 minutes if you used a stabilizer with a fuel system cleaner. This will also give it time to clean the ethanol residue and any other residual fuel remnants from the fuel system.   

5. Restart the engine and run it until it’s completely drained of gas.

6. Your next step is to remove the remaining fuel from the carburetor. This is done several ways depending on the manufacturer of your equipment. First you must find your carburetor’s fuel bowl. You can find this by following the fuel line from your fuel tank to the engine. 

  • If your fuel bowl has a drain on the bottom, loosen the drain bolt or valve and drain out the remaining fuel. 
  • If the fuel bowl has a big bolt in the middle, break the bolt loose and drain the fuel. Then retighten the bolt. 
  • If your fuel bowl does not have a drain or bolt in the middle of it, you will have to remove the fuel bowl. This can be done by removing the two screws at either corners of the fuel bowl where it bolts to the carburetor. Remove the bowl and dump out any remaining fuel. Then replace the bowl onto the carburetor.


Remember, even when the generator is not in use often, you should carry out general check-ups once a month to allow the generator to run at least 30 minutes.  Remember our safety tip: Before servicing or repairing any power equipment, disconnect the spark plug and battery cables. Remember to wear appropriate safety glasses and gloves to protect against harmful chemicals and debris.

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