Put Some Energy Into It
by Dale Gabrielse
May 1, 2009
If the air filter is not cleaned and changed, it will be prone to clogging, which causes a loss of power and shortens engine life by allowing dirt to enter internal components.
A how-to guide for generator maintenance.
Day in and day out, generators bring power to where it’s needed most. These workhorses of the worksite enable contractors to work where they need to, not where they’re forced to by existing power sources. And what thanks does this machine of ultimate convenience get? Sure, it receives fresh fuel refills and an occasional oil change, but a little more preventative care and maintenance can go a long way. Here are some tips and tricks to energize your generator maintenance program.
Daily Maintenance Checks
Although it is often the most overlooked step, daily generator maintenance is usually the easiest and quickest to perform. Making these checks every day will prevent a multitude of problems.
Dirty fuel is the cause of some of the most common problems associated with generators and their engines. Dirty fuel leads to clogged fuel lines and carburetors, which can be expensive to replace. To prevent dirty fuel from entering a generator, store fuel in an OSHA-approved receptacle and keep it out of high traffic areas where dust and debris can cause contamination. When refilling, move the generator out of windy conditions where dust is more likely to enter the fuel tank.
To prevent serious problems, check the oil before each use. Many people do not realize oil serves a dual purpose in small, air-cooled engines. Because an air-cooling system does not use a liquid coolant, it is often assumed that air alone acts as the cooling medium. Fuel and the lubrication systems also help cool these types of engines. For this reason, it is equally important to check the oil on air-cooled engines, even if the manufacturer does not claim it is needed.
Checking the condition of the air filter is another important daily maintenance practice. A clogged, wet or damaged air filter can lead to a loss in power and shorten the life of an engine by allowing dirt or water into sensitive areas.
To prevent serious problems, checking the oil before each use is a necessity.
Never use a pressure washer to clean a generator and its engine. The sudden temperature change of cold water coming into contact with a very hot engine may result in cracks and damage. Furthermore, the pressure of a power washer could be enough to break through the engine seals, resulting in water in the engine. Instead, clean a greasy or dirty engine by spraying it with a non-petroleum-based degreaser. Wait for the solvent to start breaking down the dirt, then wipe it clean with a cloth or soft brush. The engine should always be warm, not hot, when it is being cleaned. Warm water at a low pressure can be used to rinse the engine. Dry the outside immediately afterward, and then run the engine for a few minutes to help dry any parts that could not be easily dried with a cloth.
Once the equipment is clean and dry, pay particular attention to any signs of fuel leakage. If a fuel leak is detected, tighten the parts causing the leak or replace them immediately. Additionally, replace anything that is damaged, and tighten loose parts that could vibrate and potentially harm nearby components.
Besides the generator itself, it’s important to look at its location. Maintaining fuel and oil systems is useless if the generator is not placed in a safe, level operating location. Operating on an angle can cause the lubrication system to fail, locking up all the critical moving parts of the engine. In addition, an angular placement can throw off the fuel level in the carburetor, disrupting the spark plugs, pistons and crankcase.
A generator resting on soft ground, such as sand or soil, will often dig itself into the ground from vibration, creating an uneven surface that will have the same effect as setting it on an angle. In addition, discharged air from the generator will stir up dust that can be sucked into the air cleaner, shortening service life. Dust also can be trapped in the cooling air, damaging the generator’s rotor, stator and windings. If a generator must be operated on a soft surface, set it on top of a piece of plywood or a stable platform to avoid damage.
Regular Maintenance
In addition to daily checks, generator engines need weekly, monthly, semiannual and annual maintenance to retain performance and maximize the life of the equipment. Although the maintenance on all small engines follows a similar timeline, operators and mechanics should consult their operator’s manuals for maintenance requirements that are specific to their equipment. A manual log may be used for tracking maintenance checks and services to ensure they are completed, or an optional hour-meter box can be purchased and attached to a machine to digitally register hours of use.
It is important to clean and inspect the fuel strainer and fuel filter every month. Contaminated fuel that is not removed can lead to trouble with engine starts.
The air filter also needs daily and bimonthly attention. Regardless of how dirty the air filter is, clean it every 100 hours and change it monthly. If the air filter is not cleaned and changed, it will be prone to clogging, which causes a loss of power and shortens engine life by allowing dirt to enter internal components.
Most manufacturers recommend cleaning foam air filters with soapy water or a mixture of three parts kerosene and one part engine oil. After cleaning with soapy water, rinse the filter thoroughly, squeeze out excess water and blot dry with a paper towel or shop rag. Work a small amount of engine oil into the filter and blot away any excess before reinstalling it. If you’re unsure of the proper cleaning method, consult the owner’s manual. If the filter still appears dirty or clogged after cleaning, it should be replaced immediately. Another way to check for an abnormally dirty foam filter is to squeeze and release it; if it does not quickly return to its normal shape and size, replace it.
Clean a paper filter by removing it and tapping it on a hard surface to knock off any excess dirt. Do not use compressed air to clean the filter elements because it may cause tears in the paper. While manufacturers typically recommend replacing paper filters after about 50 hours of use, dusty environments will result in more frequent replacements. Checking the filter regularly ensures that a replacement is made when it is actually needed.
Inspect the spark plugs every 50 hours for damage, dirt and excessive carbon buildup. Dirty spark plugs can cause a decrease in power and poor starting performance. Spark plugs coated with a considerable amount of dirt or carbon buildup can be cleaned with a wire brush or spark plug cleaner. If the buildup seems excessive, it may be a sign of weak spark voltage, a lack of air cleaner maintenance or an incorrect fuel-air mixture. Also check the electrode gap on the spark plugs to ensure it still meets the manufacturer’s specifications, and adjust as needed. Replace any spark plugs with cracked porcelain immediately.
Additionally, it is important to clean and inspect the fuel strainer and fuel filter every month. Contaminated fuel that is not removed can lead to trouble with engine starts. Replacing the fuel line and carburetor is expensive, so it is essential to prevent unnecessary damage caused by contaminated fuel.
If there is sediment on the fuel strainer, shut off the fuel line valve before any maintenance or cleaning. Then remove, empty and clean the sediment bowl and clean the filter screen. If sediment has made it into the tank, all the fuel will need to be removed. Clean the residue from the sediment reservoir, which is the lowest point in the tank. Use a clean rag to wipe sediment from the filter element and the sides of the tank before refilling the tank with clean fuel.
On an annual basis, inspect the generator for dirty, broken and misaligned parts. Such parts can cause a variety of problems, and thoroughly inspecting the generator gives the most comprehensive view of what needs to be cleaned and repaired. Furthermore, check the fuel hose each year, and replace it if there are cracks.
Generators must always be operated on a level surface. Operating on an angle can cause the lubrication system to fail, locking up all the critical moving parts of the engine.
In addition to following a maintenance schedule, be aware of the audio and visual signs of other maintenance needs. Not addressing a small problem early on can lead to a much bigger problem in the future.
If an engine is experiencing hard starts, the valve clearance on the intake and exhaust valves should be checked and adjusted according to manufacturer specifications. When checking the valve clearance, position the piston at the top dead center of the compression stroke and ensure the engine is cold. After the clearance is adjusted, rotate the crankshaft and check the valve clearance again.
A reduction in power often is an indication that the cylinder head and carburetor need to be inspected and cleaned. Check the cylinder head’s valves, seats, ports and guides and remove any carbon or gum deposits from the components. Since water or excessive dust on the filter will likely cause engine problems, check the air filter as well.
A loosely hanging recoil rope also indicates a problem. If it looks like the rope will not completely return, the lubricant on the internal drive parts may have washed off. Remove the recoil drive assembly and apply additional lubrication to solve the problem. If the dangling rope goes ignored, it can result in a broken rope or eventual damage to the recoil starter.
Additionally, a loss of power or a smoking engine may signal an internal engine problem. Blue-colored smoke indicates that the engine is using oil. This problem tends to be more common on cold days. Look to see if the breather hoses are plugged and check the piston rings, which may be bad, to determine the cause of the smoke. If the smoke is black in color, it typically indicates that the mixture is too rich. Incorrect mixtures of air and fuel cause the majority of carburetor problems; therefore, it is important to prevent clogged jets, air passages and fuel passages that keep air and fuel from flowing freely. Check the carburetor for dirty or defective parts and clean or replace them if needed. A change in elevation also may cause black smoke, in which case the engine should be modified to handle the difference. If the basic troubleshooting maintenance techniques fail to work, have a trained mechanic conduct a leak-down test or compression test to determine the cause for any smoking or power reduction.
Like smoke colors, different noises also can indicate specific problems. For instance, if the engine begins to make a popping noise or backfire, the mixture of fuel and air is likely too lean in the carburetor. A knocking noise will generally indicate a worn connecting rod, while a tinny or metallic sound may mean something is loose.
Although it may appear time consuming to follow a strict maintenance schedule, most preventative checks for generators are fairly quick and easy to perform. Compared to the amount of time and money required to fix or replace a generator or major component, a few minutes spent on maintenance is a small investment to make. Recognizing signs of trouble and understanding generator maintenance will help operators avoid downtime, stay efficient and prevent productivity-draining repairs.
SIDEBAR: Adjusting for the Environment
Operating an engine after the mercury has surpassed 100° F also can be problematic. Ensuring dirt does not obstruct an engine’s cooling mechanisms will help prevent problems with overheating. Check and change the oil and oil filter more frequently than normal when using an engine in hot weather, and take the heat into account when choosing the oil’s viscosity.
On the other end of the thermometer, monitoring the oil’s viscosity remains important. If a cold front should move in before the oil has been changed to a more appropriate viscosity, move the machine to a warm, well-ventilated space before attempting to start the engine or change the oil.
Keeping the fuel tank full will prevent moisture from condensing inside the tank when it is cold, which can cause problems with engine operation. Ensuring the battery remains well-charged also will combat any problems an operator may face in a cold environment.
One trick to ease frustration if the generator needs to remain outside and an ice storm is anticipated is to push the throttle to the middle of its speed range. Should ice form on the linkage, it will be easier to start the engine with the throttle in this position.
Dale Gabrielse
Dale Gabrielse is the training manager for Subaru Robin in Wood Dale, Illinois.
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