A whole-home standby generator is a small engine that works hard when you need it most. Like any engine, it relies on precise mechanical timing to run efficiently and reliably. One of the most important, and most overlooked, maintenance items is a valve adjustment. When was the last time your valves were adjusted? If you don't know, give us a call!
What Is a Valve Adjustment?
Inside your generator’s engine are intake and exhaust valves. These valves open and close at exact moments to let air and fuel in, and exhaust gases out. The clearance between the valve and the rocker arm is called valve lash. Lifters open and close the engine's intake and exhaust valves.
Over time, normal engine wear and heat cycles cause that clearance to change. A valve adjustment is the process of measuring that clearance and setting it back to the manufacturer’s specification so the engine operates as designed.
This is not a guess or a visual check. It is a precise mechanical adjustment that requires the engine to be set at the correct position, measured with feeler gauges, and adjusted cylinder by cylinder.
Hydraulic vs Manual Lifters
How do I tell if I have Manual Valves?
If valve clearances drift out of spec, performance and reliability suffer. Common issues include:
- Hard starting or no start conditions
Valves that are too tight may not fully close, reducing compression. - Rough running or misfires
Improper valve timing affects combustion stability. - Loss of power under load
The engine cannot breathe correctly when the valves are out of adjustment. - Increased wear and overheating
Tight valves can overheat and eventually burn, leading to costly repairs. - Shortened engine life
Small tolerance issues add up over years of operation.
Most air-cooled residential generators require valve adjustments at regular hour or year intervals, even if they rarely run during outages. Exercise cycles still create wear and heat.
Is This a DIY Task?
It can be a DIY task if you are comfortable with engines or a savvy DIY'er. Valve adjustments do require partial disassembly, precise measurements, knowledge, and the correct tools. Incorrect adjustments can cause more harm than good. This is why manufacturers recommend valve adjustments by a certified professional rather than a homeowner task.
How Valve Adjustments Fit Into Proper Generator Care
Valve adjustments are not a standalone service. They are part of a comprehensive approach to keeping your generator reliable long term. Along with oil service, filter replacement, battery testing, and full system diagnostics, valve adjustments help ensure your generator starts quickly, carries load properly, and is ready when the power goes out.
Part of Our Semi-Annual Maintenance Options
Valve adjustments are included as part of our semi-annual maintenance options by a certified generator technician when required by your generator’s service schedule. This ensures critical engine tolerances are checked and corrected before they turn into performance issues or expensive repairs.
Routine maintenance is not just about keeping a generator running. It is about making sure it works exactly as expected when your home depends on it.
See Also:
Generac: How do I perform a valve adjustment on my air-cooled home standby generator?
VIDEO: Generac Valve Adjustment: The RIGHT Way Most Owners Never Learn (Step-by-Step)
VIDEO: Generac Generator 8kw-26Kw valve adjustment 5 minute completed.
