Why Maintenance Matters
A standby generator is a mechanical device with an engine, and like any engine, it requires regular maintenance. Neglecting maintenance is the number-one reason generators fail to start during an actual outage. It is also the most common reason warranty claims get denied.
The good news is that maintaining a standby generator is straightforward. Most tasks take just a few minutes, and the annual professional service costs $200–$400.
Weekly (Automatic)
Your generator should be programmed to run an automatic exercise cycle once per week. This typically runs the generator at no load or light load for 15–20 minutes. The exercise cycle:
- •Keeps the engine lubricated
- •Charges the battery
- •Burns off moisture in the exhaust system
- •Verifies that the generator starts and runs properly
You do not need to do anything for this — it is automatic. However, you should verify that the exercise cycle is actually running. Check your generator’s monitoring app (Generac Mobile Link, Kohler OnCue, etc.) or listen for the generator starting at its scheduled time.
Monthly Tasks (5 Minutes)
These are simple visual checks any homeowner can do:
Check the status indicator. Most generators have a green/yellow/red light or a digital display. Green means ready. Yellow or red means a fault that needs attention.
Inspect the area around the generator. Remove any debris, leaves, grass clippings, or objects that may have accumulated around the unit. Maintain at least 36 inches of clear space on all sides for airflow and service access.
Check for pests. Mice, lizards, and wasps frequently nest inside generator enclosures. Look for droppings, nests, or visible insects. If you find evidence of pests, schedule a service call.
Verify the battery charge. If your generator has a battery status indicator, check it. A weak battery is the most common reason for a no-start condition.
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Quarterly Tasks (15 Minutes)
Check the oil level. With the generator off and cool, open the access panel and check the dipstick. The oil should be between the low and full marks. If it is low, add the manufacturer-recommended oil. Do not overfill.
Inspect the air filter. Remove the air filter and check for dirt, debris, or damage. A dirty air filter reduces performance and can cause engine damage. Replace if visibly dirty or at the interval specified in your owner’s manual (typically every 200 hours or annually).
Check coolant level (liquid-cooled units only). Verify the coolant reservoir is at the proper level. Use only the coolant type specified by the manufacturer.
Test the generator manually. Use the manual start function to verify the unit starts, runs smoothly, and shuts down properly. Listen for any unusual sounds like knocking, grinding, or excessive vibration.
Annual Professional Service ($200–$400)
Once a year, schedule a professional maintenance visit with a licensed generator technician. This service typically includes:
Oil and filter change. The technician drains the old oil and replaces it with fresh, manufacturer-specified oil and a new oil filter. This is the single most important maintenance task.
Spark plug replacement. Spark plugs wear over time and can cause hard starting or rough running. Most manufacturers recommend annual replacement.
Air filter replacement. Even if the filter looks clean, annual replacement ensures optimal airflow and engine protection.
Battery load test. The technician tests the battery’s ability to start the generator under load, not just its voltage. Batteries typically last 3–5 years and should be replaced proactively.
Coolant flush (liquid-cooled units). Every 2–3 years, the coolant should be flushed and replaced. Your technician will advise on timing.
Transfer switch inspection. The technician checks all electrical connections in the transfer switch for tightness and corrosion. Loose connections are a fire hazard and can prevent proper operation.
Full system test. The technician simulates a power outage to verify the complete system works correctly: utility power loss detected, generator starts, transfer switch activates, power is delivered, and the system shuts down properly when utility power returns.
Before Hurricane Season
If you live in a storm-prone area, add these tasks before the season starts:
- •Schedule your annual professional service for April or May
- •Verify your propane tank is full (if applicable)
- •Clear vegetation and debris around the generator
- •Test the generator manually and verify the monitoring app is working
- •Confirm your emergency contact numbers for your installer and fuel supplier
Maintenance Log
Keep a simple log of all maintenance performed, including dates, tasks completed, and who performed the work. This log is essential for warranty claims and adds value if you sell your home.
What to Do If Something Seems Wrong
If your generator’s status light is yellow or red, if it fails to start during a test, or if it runs roughly or makes unusual noises, do not ignore it. Contact your installer or a licensed generator technician promptly. Small problems caught early cost $100–$300 to fix. The same problems left unaddressed can result in $1,000+ repairs or complete engine failure.
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GeneratorPrice Editorial Team
Our editorial team researches and writes every article with input from licensed generator installers, electricians, and industry professionals. We are committed to providing accurate, unbiased information to help homeowners make informed decisions about backup power.