A generator that passes its weekly self-test every Tuesday morning can still fail on day three of a winter storm. The self-test confirms the engine fires and reaches operating speed, but it doesn’t assess oil condition, battery capacity under load, spark plug wear, fuel line integrity, or how the automatic transfer switch (ATS) performs through a sustained outage. Those are the conditions that actually separate a reliable backup system from one that quits when you need it most.
We’ve been servicing generators in Montgomery County for over 20 years, and the calls we dread most come during active outages. An annual maintenance appointment exists precisely to prevent that scenario. Here’s what a thorough visit should cover and why each piece matters.
What Your Generator Can’t Check on Its Own
Generac’s weekly exercise cycle starts the engine, runs it briefly under minimal load, and shuts it down. That sequence confirms ignition, but it doesn’t put meaningful stress on the system. Oil degrades over time regardless of runtime hours. Battery charge cycles slowly wear down capacity. Fuel sitting in supply lines and the carburetor oxidizes and forms deposits even when the engine rarely runs. A generator that sees only its weekly self-test accumulates wear and degradation between those brief cycles without any mechanism to catch it.
FEMA is direct on this point: emergency generators require routine servicing that includes oil changes, inspections, and operational testing to maintain reliability during extended outages. The weekly exercise cycle isn’t that servicing.
The Engine & Fluid Services Every Appointment Should Include
Generac specifies an oil and filter change annually or after 100 hours of runtime, whichever comes first. For most residential units that see relatively little actual outage runtime, the annual calendar interval is the controlling factor. Fresh oil protects the engine during the high-demand startup phase of an outage, when the generator goes from cold to full load in seconds. A complete engine service also covers:
- Air filter inspection or replacement: A clogged filter restricts combustion air, reducing output and raising engine temperature. Filters in Maryland’s pollen-heavy spring and summer seasons can clog faster than the annual interval suggests.
- Spark plug inspection: Worn or fouled plugs cause hard starts, misfires, and incomplete combustion. A technician checks gap, condition, and electrode wear and replaces plugs when they’re approaching end of useful life rather than waiting for a failure.
- Cooling system check: Liquid-cooled units require coolant level inspection and hose condition review. Air-cooled units need their cooling fins cleared of debris and inspected for damage that reduces airflow.
- Fuel system integrity check: Every fuel line, connection, and fitting is inspected for cracks, softening, or leaks. Varnish deposits from degraded fuel are one of the most common causes of startup failure after a period of low use.
Battery, Electrical, & Transfer Switch Checks
Battery failure is one of the leading reasons a generator cranks but won’t start. A visual inspection tells you almost nothing useful. A battery load test draws actual current under controlled conditions to measure real performance under electrical demand. It’s the only way to know whether the battery will hold up when the generator needs to start at 2 a.m. in January.
Electrical connection inspection goes beyond the battery terminals. A technician checks wiring throughout the control panel, inspects the alternator for corrosion or wear, and confirms all connections are tight. Loose or corroded connections cause voltage fluctuations and intermittent startup faults that are difficult to diagnose during an active outage.
The ATS simulation test is one of the most important steps in the entire appointment. The technician manually simulates a utility outage and confirms the full sequence: the ATS detects the loss of grid power, disconnects the home from the utility feed, signals the generator to start, accepts the load, and transfers back to utility power cleanly when the grid is restored. If any step in that sequence fails, you find out during a controlled test rather than a real outage.
Extended-Interval Items That Rotate Into Your Annual Visit
Not every maintenance task happens every year, but many are tracked and addressed during an annual maintenance appointment on a rotating schedule. Knowing what these are helps explain why a thorough service history matters.
Battery Replacement
The engine starting battery should be replaced every 3 to 5 years. Where the ATS includes its own battery, that unit follows the same interval. A technician who has your service records knows where you are in that cycle and can flag the replacement before the battery fails rather than after.
Internal Fuel Hose Replacement
Internal fuel hoses are recommended for replacement every 6 to 7 years. These components aren’t visible during routine owner inspections. Degradation that reaches the interior of a fuel line creates a contamination and leak risk that an annual external inspection alone won’t catch.
Valve Adjustment
On mechanical valve units, exhaust and intake valve adjustment is indicated every 300 to 400 hours of runtime. A technician reviews runtime logs alongside the service calendar to determine whether this service is due during any given visit.
What Certified Service Does for Your Warranty
Generac’s five-year limited warranty ties coverage to scheduled maintenance performed by an authorized and certified Generac service dealer. Work performed by uncertified technicians is specifically excluded. If service records show the maintenance history was performed by someone outside the authorized network, Generac can deny the claim.
Our Power Pro Elite+ status with Generac means our technicians have factory-direct training, access to genuine OEM parts, and the credentials to perform and document warranty-qualifying service. Each visit produces a record that documents what was done, what was inspected, and what was replaced. We recommend keeping those records with the unit’s original paperwork. That documentation is what you’ll need if a warranty claim is ever filed.
A related item worth confirming during any service appointment is the status of the Generac Mobile Link remote monitoring connection. Mobile Link sends real-time status alerts and maintenance notifications to your phone or computer. A technician can verify the device is connected and transmitting correctly. It’s a small check that’s easy to overlook but gives you visibility into the system between scheduled visits.
When to Schedule in Montgomery County
Montgomery County is served by PEPCO and BGE, and the county’s Office of Emergency Management identifies snowstorms, hurricanes, tornadoes, and thunderstorms as recurring hazards that cause utility disruptions here. NOAA places the Atlantic hurricane and severe storm season from June 1 through November 30, with the county actively urging preparedness measures throughout that window.
Late spring is the most practical time to schedule annual generator maintenance in this area. Service completed in April or May means the system is fully inspected and any issues are resolved before the peak outage months arrive. Waiting until a storm is already in the forecast typically means appointments are backed up and parts may be on delay.
A secondary inspection in the fall can make sense for units that see heavy use or exposure during the summer. Maryland’s pollen season is hard on air filters, and fuel system issues that develop over a wet spring humidity season can surface before heating season if caught early. Ask your technician what they observed during the spring visit and whether a fall check makes sense for your specific unit.
When the appointment is done, you should have a service record in hand and a clearer picture of where your system stands. If you’re ready to schedule or want to talk through what your unit might need, reach out to Power Watch Systems, your local Power Pro Elite+ certified provider serving Montgomery County, at (610) 890-7693.