Generator Run Log: Tracking Hours, Oil and Fuel in a Long Outage
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A generator run log is a sheet of paper, kept beside the unit, where you write each start and stop, each oil check and each refuel with the time. In a multi-day outage it answers the questions you will otherwise argue about at 3 a.m.: how long has it been running, when did we last look at the oil, and when did we last add fuel? The log does not set any intervals. Your owner's manual does that, and the log simply makes sure you follow it.
Why keep a log at all
Memory fails in a long outage. Sleep is broken, people swap shifts, and one person assumes another topped off the tank. A written log lets anyone in the house pick up the routine without guessing. It also gives you real numbers for later, such as how many hours a tank lasted under your actual loads, which no spec sheet can tell you for your house.
For the basics of runtime and refueling in a multi-day event, see our guide on how long a generator can run. This article is only about the paper trail.
The log is a habit, not a safety device. Run the generator outdoors only, away from windows, doors and vents, never in a garage or enclosed space, and keep a battery-powered or battery-backup CO detector working in the home. Never plug the generator into a house outlet. Your manual and the CDC guidance still decide placement.
What to write down
Keep it to a few columns so people actually fill it in. Here is a layout you can copy onto a ruled page.
| Column | What goes in it | Why it helps |
|---|---|---|
| Start and stop time | Clock time each time the engine starts or stops | Gives you total run time even without an hour meter |
| Hours reading | The hour meter number, if the unit or an add-on has one | Lines up with the service intervals in the manual |
| Oil check | Time checked, level okay or topped up | Shows the check happened and who did it |
| Fuel added | Time and rough amount, and the fuel type | Builds your own hours-per-tank figure |
| Loads connected | Which appliances were running | Explains why one tank lasted longer than another |
| Notes | Noises, surging, smells, trips, leaks | Early warning for the service shop |
| Initials | Who did the entry | Removes the guesswork at handover |
Let the manual set the intervals
Different engines call for different checks, so copy the intervals from your own manual onto the top of the sheet. Two examples of what manuals and makers say: one owner's manual says to check the oil level before each use, and a Briggs & Stratton maintenance page advises checking the dipstick every time you add fuel and keeping it at the full mark. Tying the oil check to the refuel is a handy habit, but your manual comes first.
The same Briggs & Stratton page notes that many units shut down automatically when oil runs low, which is another reason to check on a schedule rather than waiting for the engine to stop. If yours shuts itself off, start with the troubleshooting pages in your manual.
Refuel entries: stop, cool, fill, record
Each refuel gets a line. The safe sequence matters more than the note. University of Georgia Cooperative Extension advises letting a hot generator cool before adding fuel, because spilled gasoline on a hot unit can ignite, and cleaning up spills right away. One manual adds that you should not fill the tank while the engine is running or hot, should fill outdoors, should use an approved container, and should leave room for fuel expansion.
Shutting down for each refuel is a decision you make with your manual, since it affects how long the house is without the loads. Plan the stop for a moment when a short interruption does little harm, and write the stop and restart times in the log. Keep spare fuel in sealed, labeled containers away from living areas, as UGA Extension advises, and note the date you bought it. Our fuel storage guide covers storage.
Buy a container made for the fuel your generator uses, and keep it sealed and labeled. Check your manual for what it recommends.
Counting hours: meter, clock or both
If your generator has a built-in hour meter, copy its reading at each entry. If not, an add-on meter is cheap and removes the arithmetic; our hour meter guide explains the types. Otherwise the start and stop times in the log are enough: add them up at the end of each day. A phone is fine as a clock, but write the times on paper in case the phone dies.
Counts run time so the log and your manual's service intervals line up. Check how the type you choose attaches to your engine.
A rhythm for day one, day two and day three
Three habits keep the log honest. Write the entry when you do the task, not at the end of the day. Use the same units every time, so a quick glance shows the trend. And leave a blank line rather than a guess when you missed a check, because a visible gap tells the next person to look more closely.
You do not need a complicated routine. Pick fixed times for a walk-around, and use them every day. At each one, look at the unit from a safe distance, listen to the engine, check for leaks or smells, glance at the cords, and make the log entries your manual calls for. Write anything odd in the notes column the moment you see it, since "it sounded different around lunch" is more useful to a repair shop than "it ran rough sometime."
Take the first full tank as your baseline. Note how many hours it ran under your real loads, then compare later tanks against it. A big change in hours per tank, with the same loads, is worth a closer look at the engine, the fuel and the air filter.
After the outage: use the log
Total the hours, then check them against the maintenance pages in your manual. One owner's manual says to change the oil after the initial break-in period, so a new unit that has just run a long outage may be due. Our break-in oil guide and maintenance schedule go through the usual items. Staple the log pages together, date them and keep them with the manual. A shop can use them, and they back up a warranty claim if you ever need one.
If you have not yet run the unit under real loads, do that first with our pre-season load test routine, and write down the result on the same kind of sheet. Our outage plan sheet pairs well with the log.
Keeps the log legible if it gets damp. Write in pencil or a pen made for wet paper.
Write the time of every start, stop, oil check and refuel, copy your manual's intervals to the top of the sheet, and always shut down and cool the unit before adding fuel. The log supports the manual and never replaces it.
Frequently Asked Questions
Start and stop times, an hours reading if you have a meter, oil checks, fuel added with time and amount, the loads connected, and notes on anything unusual. Add initials so handovers are clear.
As often as your owner's manual says. One manual says to check before each use, and a Briggs & Stratton page suggests checking each time you add fuel. Follow your own manual.
Not strictly. Written start and stop times can be added up each day. A meter saves the arithmetic and lines up neatly with the service intervals in your manual.
No. Stop the engine and let it cool first, because spilled fuel on a hot unit can ignite. Refuel outdoors from an approved container and wipe up spills immediately.
Sources and verification
The oil, refueling and storage points come from these pages. Intervals and capacities for your unit come from your manual.
- Generac GP3250 owner's manual: Example of a manual that has the oil level checked before each use and a low-oil shutdown sensor.
- Briggs & Stratton, generator maintenance tips: Check the dipstick each time you add fuel; many units shut down on low oil; inspect filters and plug on the manual's schedule.
- University of Georgia Cooperative Extension, Safety Tips for Portable Generator Usage: Cool before refueling; sealed, labeled fuel containers away from living areas; clean up spills.
- Manual for a portable inverter generator, model 100306: Do not fill while running or hot, fill outdoors from an approved container, leave room for expansion; change oil after the break-in period.
- CDC, carbon monoxide: Never run a generator inside the home or garage; use a battery-powered CO detector.
No oil intervals, tank sizes or run times are quoted. Read them from your manual, and ask the maker or a service shop about anything the manual does not cover.