Welcome to our Generator Maintenance Guide. The goal is to help you keep track of everything you need to do to keep your portable generator running smoothly year after year. Like it or not, it means you’ll have to get your hands dirty from time to time, but don’t let that scare you.
Treat it well & it will be there when you need it most
Do you normally end up being the person who is embarrassed because your generator fails while everyone is looking on? Does your pulse start racing, or do you break out in sweat when you have to prepare your generator for a major storm? Does it worry you that your generator may not start when you need it the most?
In our comprehensive guide to generator maintenance for Portable and Standby Generators I explain how you can avoid those uncomfortable situations. This article will equip you with all the basic knowledge you need to ensure your generator is always performing as it should. Please understand that this is not a complete guide to servicing your specific model. That pertinent information is only available in your owner’s manual.
Those with a love of reading or who studied at varsity often proudly display their collection of books in a small library in their study. They find it hard to part with their valuable sources of information, even though they may never again use them. Not surprisingly then that I’m also the proud owner of a library of books; service manuals for everything I own, or ever owned. It’s not as expansive nor as impressive as some private libraries, but I use it often. When I unpack a new tool the first thing I do, is read the manual, and then it goes straight to the library. My wife refers to it as my dirty library because I often use service manuals when my hands are dirty. You may prefer to use an online library, or download files and keep it on your computer, but that is fine, at least you keep it safe.
Fortunately, the same basic maintenance tasks are performed on all generators. You will also find that the engine is the one that needs most of your attention. The alternator and other components like inverter modules and the components on the interface panel are not serviceable or do not need regular attention. A good cleanup, inspection and tightening of bolts and screws is all it needs from time to time.
VIDEO | Basic Portable Generator Tips & Maintenance
The Importance of Generator Maintenance
Careful generator maintenance is essential to ensure trouble-free, economical operation. It will ensure the generator will start and run smoothly and will help reduce air pollution. Once you understand how and why, you will no longer fear the machine. You will no longer apprehensively approach the generator with a silent prayer that it shall start this time. If it fails, you will be equipped to resolve the issue efficiently and without any anxiety.
To properly care for your generator, you should find and follow the recommended maintenance schedule which applies to normal operating conditions. Should you operate your generator under sustained high-loads, high-temperature operation, or dusty conditions, the regular maintenance schedule is not suitable. Then I recommend that you shorten service intervals to better protect the generator. You may also consult your servicing dealer for recommendations applicable to your individual needs and use.
I urge you to routinely inspect your generator for loose bolts, fuel leaks and oil leaks and to do the basic generator maintenance tasks using basic hand tools. It will help you to become more acquainted with the generator and you will find that it will serve you better.
Generator Maintenance Safety
When doing maintenance, using tools, you are exposed to some hazards. Whenever you use tools and handle machinery you must be careful. Wear all the safety equipment at your disposal, think clearly and act decisively. When doing generator maintenance, you will want to start the generator to test that it is running properly. It is all too easy to forget that a tool is still resting on the frame or other parts when you start the engine. The vibrations of the machine can cause it to drop in and damage some parts, you must always be vigilant and place tools safely. Never place tools on a machine or near moving parts.
— Carbon monoxide poisoning from engine exhaust
It is tempting to start and test a generator in the garage or workshop but Carbon monoxide poisoning is always a possibility when operating a generator in an enclosed space. You may feel a quick check is fine when you keep it short, and the area is well ventilated. But it can be dangerous and should be avoided.
Early symptoms of carbon monoxide exposure include nausea and dizziness. Continued exposure to carbon monoxide can cause headache, fatigue, shortness of breath, loss of muscular coordination, loss of consciousness, and then death. I always recommend installing battery-operated carbon monoxide alarms or plug-in carbon monoxide alarms with battery back-up in your workplace. It will alert you to potentially dangerous levels of carbon monoxide.
Generator Maintenance starts with cleaning and inspecting the generator. Generators do not get very dirty but must be cleaned before a service. While you clean the machine be sure to remove all dirt and debris from the inlet ports to ensure the engine does not run hot. Cleaning the generator also ensures that dirt will not enter the motor internals or the alternator internals when you service it. When dirt enters an engine, be it while changing oil, the spark plug, and even the air filter, it drastically shortens its serviceable life.
— Recoil Starter
Even if your generator has an electric starter it is still equipped with a recoil starter. You should at least pull the rope out completely and inspect it. If it is frayed or damaged in any way, replace it. Also check the rope handle for cracks.
For a manual start generator, the rope and the recoil spring must be inspected at every service and you may need to replace the rope more often. The best way to inspect and service it is to remove the recoil starter unit from the engine. It is normally tied down with four screws. Turn it over and place it on the workbench. To remove the rope, you pull it out all the way and remove the knot from the pulley side of the starter. Now you can carefully inspect the rope and replace it if necessary.
To inspect the recoil spring, you must remove the screw holding the retainer and then remove the retainer and place it to one side. Remove the pawls and pawl springs if present. Remove the pulley and flip it over to see the spring. These springs tend to crack and eventually break near the center where it attaches to the pully. Most manufacturers sell the pully and spring as a set, so it is easy to replace. The replacement parts also come with installation guides.
Electric Starter and Battery
The electric starter should never fail you. If it does you may have to take the generator to a service center to have it serviced or replaced. The battery cannot be serviced, it only needs to be kept clean and recharged often. Should your generator fail to start, refrain from using the starter for too long. These batteries should not be drained to low, it damages the internals. If the generator fails to start you must deal with it and not damage the battery.
Engine Oil Level Check
You should check the engine oil level every time before you use your generator. Conscientiously keep the oil level at the recommended mark, do not let it drop somewhat before you deem it necessary to top up. Almost all small engines splash the oil inside the engine to lubricate the parts. The motion of the crankshaft picks up the oil and splashes it all over. If the oil level is low it will not lubricate the engine properly.
These engines also burn some oil during operation and the level will slowly drop while you use the generator. Therefore, it’s best to start the generator only when the oil is filled to the recommended level. If not, it may even drop to the point where the low oil level sensor will let the controller stop the generator. It can be very inconvenient because you must allow the engine to cool down before you top up the oil. To avoid this inconvenience, and the embarrassing moments, check the oil level before you use the generator.
First, it is important that you position the generator on a level surface. If not, you could over- or under-fill with oil. Locate and remove the oil filler cap, where to find it, and how it shows the oil level will vary. You may need to find your service manual or look it up online. It is normally a winged cap at the lower end of the engine and you can open it by hand. Some have a small dipstick attached while on many engines you simply fill it till just before it spills.
— Engine Oil Recommendations
I think we all know what engine oils do, well, at least you should have some idea. Engine oils, like all oils, reduce friction. Friction is a force that resists two solid surfaces sliding against each other. It even happens when you rub your hands together. The construction of the engine is such that metal surfaces slide against each other and therefore creates friction. Engine oil clings to these surfaces and creates a small barrier of the oil film between the parts. Friction creates heat and the heat can become so intense that the metals can weld together. Friction because of low oil levels shortens engine life and increases fuel consumption. When the engine isn’t running, oil drips off the internal engine components, that’s why most engine wear comes from startup. When you store the generator, the process continues and the engine internals is even dryer.
Provided the oil is in good condition it prevents metal to metal contact, keeping the surfaces cooler and reducing friction. The conditions inside the engine, temperature changes, absorption of water from the air and carbon deposits, wear down the oil. It becomes dark colored and may even have a foul smell, a clear sign that you are now allowing friction to eat into your pocket. Believe me, it is less expensive to replace the oil when you should.
To optimize performance, maximize efficiency, and minimize exhaust emissions; find and follow the procedures outlined in the service schedule. It is the best guide to servicing your generator and the engineers recommend oils and oil grades that best protect the engine. Key to an engine’s health is the type of oil used, which means using manufacturer recommended oil is critical in protecting your generator engine.
When you stare at the strange numbers on the bottles of oil in the parts store, the choices will easily confuse you. Now, I can explain them, you may even look it up on the internet but you will forget what they mean. It’s a situation that can easily lead you to buy the wrong oil type.
This is what I do to avoid that, I keep a note on my smart phone. We all carry these things with us and all of them have a facility to store information. I use the notes app on my phone and I note all the information I will need when buying generator maintenance parts. Then the choice is simple, just pick up the oil type and filter recommended in your owner’s manual. Also do not try to substitute, if the manufacturer recommends SAE 5W50 it’s what you should buy.
The difference between synthetic oils and conventional oil, and the debate about which is best, needs some explaining. Oil producers categorize both conventional and synthetic oil by viscosity, otherwise known as the weight of the oil. You may read that synthetic oil is more viscous than conventional oil, but, if it has the same rating, the viscosity is the same. There is also the notion that they develop synthetic oil in a laboratory and it does not contain conventional oil, therefore being synthetic. It is not. Synthetic oil is conventional oil that undergoes a different distillation process and with more additives added. It improves the performance of the oil under extreme conditions.
Synthetic oil is great for your high performance engine that is exposed to heavy traffic conditions, changing weather and engine loads. For a small stationary engine like the one used in a generator you only need to use the recommended oil. If the manufacturer recommends or approves synthetic oil, you may use it. Otherwise, conventional oil of the correct grade is adequate.
Checking and Adjusting Valve Lash
Checking and adjusting valve lash of your generator is an important task that is feared by many and therefore neglected. It must be done in a timely manner and correctly or your engine can suffer major damage. Unless you have the proper tools and are mechanically proficient, valve lash should be serviced by your dealer. If, however, you feel confident that you can do it, it is time to visit your library of service manuals and find the manual for your generator.
Spark Plug Maintenance
The spark plug must be checked and cleaned after every 100 hours of use and it must be replaced after 300 hours of use. Do you realize that after 300 hours of use the spark plug in the generator engine fired 32 850 000 times? It is also exposed to the same number of explosions and exposed to tip temperatures between 932°F and 1562°F. It is a hard working part of the engine and it is a critical component that influences performance and consumption.
The spark plug in your generator was chosen carefully after many hours of testing. Always use the spark plug recommended by the manufacturer. Every spark plug manufacturer produce more than 1,000 different types of spark plugs to suit the specific conditions in different engines.
Air Cleaner Service
The air filter must be cleaned as recommended in the service manual. Most likely every 50 hours of use. Some filters can be cleaned while other must be replaced, you will find the information in the manual.
Cleaning the Spark Arrestor
Check and clean the spark arrestor after every 100 hours of use. It is usually visible from the end of the exhaust muffler and removed by undoing a screw or clip. Remove it from the exhaust muffler and use a soft wire brush to clean the spark arrestor screen. You should replace it if it is damaged.
Check all Electrical Connections and Receptacles
At least once a year or when you remove the generator from storage, you should check all electrical connections. Use a circuit tester in resistance mode to verify that all connections are making good contact. Make sure all the connections are secure and when you start the generator measure the voltage outputs to see if they are still within limits.
Make it a habit to check the Ground Fault Circuit Interrupter (GFCI) receptacle and all other electrical components on the control panel. While it is operating normally, the GFCI indicator will continuously indicate green. You should do this every time you do maintenance or removing it from storage. Moisture or ice can cause a malfunction or short circuits in electrical components that could result in electrocution.
Check the Extension Cord for Cracks
Something that some owners’ manuals ignore in a maintenance procedure is to inspect the extension cord that you use with the generator. Some may recommend using grounded 3-prong extension cords, and inspecting cords and plugs, to replace if damaged. It is an important point though; a damaged cord is dangerous and may cause the GFCI circuit to trip the supply. When that happens, it will be difficult to determine why, and lead to another embarrassing moment.
Generator will not start —
Why will a generator not start? If the carburetor receives fuel and the spark plug receives a spark it should start, not so? No, it is not that simple. Those among us that experienced the frustrations of a generator refusing to start know that. You become so worked up that you forget the basics. Therefore, I will help you with a simple logical checklist of things to do.
- The first thing to check is to make sure the main switch is on.
- Make sure the generator has fuel and the fuel cock is open.
- Check the oil level to ensure it is correct AND that the oil alert light remains off. If it is on and the oil level is at the correct level, the sensor is faulty.
- Think back, are you sure the fuel in the tank is good? Maybe you stored the generator without treating or draining gasoline or you refueled with bad gasoline. You may need to drain the fuel tank and carburetor and refuel with fresh gasoline.
- You used the choke, possibly for too long, therefore the spark plug is wet with fuel. We also say we flooded the engine. One way of correcting it is to wait awhile and see if the spark plug will dry out. The fastest way is to remove the spark plug and dry it.
- While the spark plug is out, use the opportunity to inspect it, and set the gap using the information you saved on your phone. Connect the spark plug to its wire and rest the spark plug against the metal part of the cylinder head. Switch on the generator and try to start it while you keep an eye on the spark plug to see if it generates a spark. The spark must be blue to white colored and you should hear it.
- If you see a spark, then the engine should start and you can reinstall the spark plug.
- Before you try to start it again make sure the fuel filter is not restricted and fuel reaches the carburetor.
- Try to start the engine again, this time knowing the fuel is good, it enters the carburetor, the spark plug is dry, and it receives a spark. Therefore, it should start.
- If it still fails, there may be a more serious problem; the spark timing can be out, a valve is stuck open, or the valve clearances are too small. Refer to the shop manual and if you feel confident that you can continue; do so. If not, take the generator to an authorized service dealer.
Engine lacks power
If the engine lacks power, sputters and takes up speed slowly, it needs your immediate attention.
- One cause is that the air filter is restricted. Clean or replace the air filter according to your service instructions.
- It is also possible that the fuel is bad, even though the engine starts. You may have stored the generator without treating the fuel or draining the gasoline, or you refueled with bad gasoline. The only solution is to drain the fuel tank and refuel with fresh gasoline.
- A restricted fuel filter will starve the engine of fuel and you must replace it.
- Make sure the spark arrestor is clean.
- If it is still the same, take the generator to an authorized service dealer, or refer to the shop manual.
No Power at the AC Receptacles
The engine fires and there is no power at the AC outlets, one cause is that the overload trip acted. An output indicator is that is off, and the overload indicator is on usually shows it.
- Check AC load, remove all AC connections, try to reset the AC circuit protector, stop and restart the engine.
- Another possibility is that the GFCI system at the 120 V 20 A duplex receptacle activated. Once again unplug the appliance from the receptacle and test the GFCI. You may need to replace or repair the appliance or power tool.
- If all your attempts fail, stop and restart the engine. If it is still faulty, it is time to visit the dealer.
Service at a Certified Manufacturer Service Center
When things fail that you cannot service like the alternator, inverter module, voltage regulator or the GFCI trip, you must hand it over to a reputable service center. Some of These components are not within easy reach, need special tools and will mostly need a replacement. It’s important to have your generator take care of at a certified manufacturer repair center. This is essential to maintain your warranty and to ensure your generator is fixed properly. There’s no shortage of shoddy repair centers in the world. All you have to do is visit the manufacturer site and find their ‘service center’ page.
For example :
- Honda certified repair centers. Click the “service” checkbox for authorized repair centers.
- Yamaha certified service centers : Choose “service” or “service and sales” in your area.
Any reputable brand will have a list of authorized service centers. If not, I would not recommend buying that brand of generator.
Storing the generator is an important part of maintenance. If done properly it will extend the generator’s expected life, the generator will also perform as expected when removed from storage. I often read storage recommendations that they break down into short term, midterm and long-term periods. My first reaction to these recommendations is that I’m not likely to know how long the generator will be in storage. It may be because I consider my generator to be a standby unit, I only use it during power fails. Therefore, the storage period is unknown to me.
When you examine storage procedures from different brands you find a common thread. Whenever you stop the generator to put it aside for a period, drain the carburetor. How you do it differs, it is not always possible to stop the generator by turning the fuel valve to the off position. It is because not all generators use a manual valve and you may need to drain it differently.
Gasoline may gum up and clog the carburetor if the generator is not run within 4 weeks. To avoid this, you drain the carburetor, and I recommend doing it every time you stop the generator. Be sure you disconnect all appliances from the generator if you will run the carburetor dry from fuel starvation.
Whatever the method used to drain the fuel, please do so safely. Fuel is highly combustible and fuel vapors may conceivably explode when exposed to open flame. Therefore, if you drain the fuel from the carburetor do so outside and not in an enclosed space.
The manufacturers that encourage mid-term storage procedures usually recommend that you either drain the fuel tank or use a fuel stabilizer. With the addition of a properly formulated fuel stabilizer, gasoline in the generator tank has a maximum shelf life of up to 1 year. Provided you store it in a cool, dry place. To me, the problem with the fuel stabilizer is that you may not realize that the year has passed and so end up with foul fuel. I prefer to empty the tank; it avoids all issues with stale fuel, plus; you save some money by not buying fuel stabilizers. You will also not have to cope with gas vapors in your storage space and you always use fresh fuel.
The top end of the cylinder also needs some attention, you need to lubricate it with a small amount of oil. During normal use, it burns away all the oil in the top half of the cylinder. Leaving the cylinder walls dry, exposing it to a possibility that the cylinder can rust. So, you remove the spark plug cap and spark plug and pour about a teaspoon of oil into the cylinder. Slowly crank the engine by pulling on the recoil cord to distribute the oil and lubricate the cylinder. Next you reinstall the spark plug and spark plug cap and clean the generator to ensure there are no oil spills.
Slowly pull the starter grip while the start or run switch is off until you feel the resistance of compression. Because the piston is coming up on its compression stroke both the intake and exhaust valves are closed. With the valves closed, the cylinder walls lubricated and the spark plug in place rust will not attack the engine.
It is normally possible to use the drain bolt on the carburetor to empty any excess gasoline from the gasoline tank and carburetor into an appropriate container. You may need to use a funnel and hose under the carburetor drain bolt to avoid spillage. When you are sure you drained all the fuel you replace and tighten the carburetor drain bolt. You should either use or properly dispose of the drained gasoline and please follow local regulations or guidelines.
The generator is now ready to be stored away in a cool, dry place and out of direct sunlight to protect rubber components. With the top end lubricated, and all fuel drained, we can leave the generator in storage for as long as necessary. While storing it I recommend putting the wheel axle on some blocks so the wheels do not support the generator but hang freely. In doing so, the wheels will not develop a flat spot.
The battery also needs some attention and I prefer the only method that does not rely on my memory. To be sure nothing can drain the battery it is best to undo both battery cables at the battery. Now we still face another problem. Batteries have so-called internal leaks that slowly drain the battery, making it necessary to recharge the battery from time to time. It is best to use a small storage/maintenance charger that will monitor the battery and recharge if from time to time.
Removing your Generator from Storage
When you remove the generator from storage, you will have the assurance that the generator will start and run as it should. You only have to reconnect the battery, check the oil level and fill up with fuel, close the choke, switch on, and start the engine.