Generator maintenance checklist: be ready for the next power cut
A generator spends most of its life switched off, then has to work perfectly the moment the power goes. Most failures to start come from a few simple things that are easy to prevent.
Why generators fail to start
The usual causes are old fuel, dirty or low oil, a clogged air filter, a worn spark plug (on petrol sets) and a weak battery (on electric-start sets). All of them are quick to check.
Run it every month
Start the generator once a month and let it run for 10–15 minutes with a light load connected, outdoors. This keeps the engine lubricated, the fuel moving and the battery charged, and it shows you any problem while there is no emergency.
A quick monthly check
- Engine oil level — top up or change if it is low or dark and dirty
- Air filter — clean or replace if it is clogged with dust
- Fuel — use fresh fuel; petrol left in a tank for many months can go stale
- Spark plug (petrol) — clean it or replace it if it is dirty or worn
- Battery (electric start) — keep the terminals clean and the battery charged
- Leads, plugs and sockets — look for cracks, burns and loose connections
Service it on schedule
Change the oil and filters at the intervals given in the manual, and at least once a year even if the generator has hardly been used. Oil breaks down with time, not just with running hours.
Before you store it
- Follow the manual for draining the fuel or adding a fuel stabiliser if it will sit for a long time
- Wipe it clean and store it somewhere dry, covered and ventilated
- Keep a spare spark plug, air filter and a litre of the right oil with it
Safety reminders
- Always run a generator outdoors, away from windows and doors
- Switch it off and let it cool before refuelling
- Never connect it to the building wiring without a proper changeover switch fitted by an electrician