Skip to content 
f you’ve never seen what actually happens during a standby generator service call, it probably sounds like a mystery box: someone shows up, pops the panel, does something for an hour, and leaves. There’s a real generator maintenance checklist behind that visit. It’s the same one we cover in our Whole-Home Generator Maintenance Guide, but here’s what it actually looks like in practice, step by step, because it’s the difference between a generator that starts when the power goes out and one that doesn’t.
We walked through a full service visit from start to finish and filmed the whole thing. You can watch the full walkthrough on our YouTube channel. Here’s what’s happening at each step, and why it matters.
Step One: Check the Hours, Not Just the Calendar
Before anything else, the tech pulls up the hour meter. A standby generator doesn’t age on a calendar. It ages on runtime hours, especially with a weekly auto-exercise cycle running in the background whether anyone’s watching or not. On this unit, the meter showed 40 hours total, with 33 of those logged since the last service. That gap helps the technician understand how much the generator has run, whether from scheduled exercise cycles, outages, or manual operation.
Homeowner takeaway: if you don’t know your generator’s current hour count, that’s the first thing to find out. It’s the first item on any real generator maintenance checklist, and it matters more than “how many months has it been.”
Step Two: The Two-Pass Oil Drain
Oil changes on a generator aren’t a one-and-done drain. On some generators, a thorough service may include a second extraction pass to make sure old oil isn’t sitting in a low spot in the pan or filter housing. On this service, the technician performed a second extraction pass to remove as much used oil as possible.
There’s a smaller detail worth mentioning too: the drain pan gets positioned carefully so old oil doesn’t stain the customer’s concrete. It’s a small thing, but it’s the kind of detail that separates a clean job site from one the homeowner has to deal with after the crew leaves.
Step Three: Filters, Then Spark Plugs
The oil filter is replaced during the service, and the fuel filter is replaced according to the manufacturer’s maintenance schedule. On the spark plug side, both plugs get removed for inspection and replaced as needed, or according to the manufacturer’s maintenance schedule.
One convenience worth noting: on this unit, the rear spark plug was accessible without removing the back panel, which isn’t true on every model. If you’re comparing generator installation options, ease of routine service access is worth asking about up front. It affects what maintenance costs you over the life of the unit.
Step Four: Battery Terminals, and a Myth Worth Retiring
Battery terminals get cleaned and treated with an anti-corrosive coating when necessary. This is a simple step, but it’s one of the more common causes of generator starting problems. A corroded terminal can look “fine” and still be feeding the starter a weak connection, which shows up as a no-start at the exact moment you need the generator most.
One myth worth clearing up while we’re on the subject: you’ll hear people say cola will clean battery terminals. It’s mild carbonic acid, so it can knock off some buildup, but it’s not a substitute for a proper battery terminal cleaner, followed by dielectric grease (where necessary). Besides, leaving a sugary residue on electrical contacts isn’t going to do you any favors. Stick with the tools made for the job.
Step Five: The Recap Every Homeowner Should Hear
A good technician closes out the visit by running through the generator maintenance checklist out loud, before packing up: oil changed; oil and fuel filters replaced and labeled; air filter replaced; battery terminals cleaned and treated. It’s a small habit, but it’s also a built-in accountability check. Nothing gets skipped quietly.
On this visit, the crew also left extra oil on site so the homeowner has it on hand for a future top-off between services. It’s a small thing, but it’s the kind of follow-through that keeps a homeowner from scrambling later.
Step Six: Firing It Back Up, Load Testing, and Auto-Exercise
Once everything’s reassembled, the unit gets started and brought up under load to confirm it’s operating normally. Oil levels get checked again once the engine’s warmed up, since oil expands slightly with heat and a “full” cold reading can look different a few minutes into a run.
From there, the auto-exercise function gets tested, including running through the unit’s burnoff cycles if it has them, which help clear condensation and unburned fuel residue out of the exhaust system after periods of light or no-load running. This is also where the automatic transfer switch gets confirmed to be working correctly. It’s the component actually responsible for sensing an outage and switching your home over to generator power in the first place.
On this visit, the final oil level came in a hair over the “full” indicator. This is worth noting rather than ignoring and something to recheck once the unit’s been fully cycled. That kind of honesty about small details is exactly what a maintenance visit should catch.
Why This Matters Before You Need It
The entire point of a standby generator is that it starts when you need it. That only holds up if someone’s actually checking runtime hours, doing full oil and filter services, keeping the battery and terminals clean, and verifying the unit under real load, not just assuming it’s fine because it’s quiet in the garage.
If it’s been a while since your generator had a real service visit, not just a glance, contact our team, or learn more about our standby generator installation services in Rapid City. We’ll check the hours, do it right, and make sure it’s actually ready the next time you need it.
