Symptoms
- Visible smoke while running
- Burning oil smell
- Smoke worse at startup or under load
- Oil consumption higher than normal
Likely causes
- CommonOverfilled engine oilExtra oil gets drawn into the combustion chamber and burns off, especially noticeable at startup.
- CommonGenerator run or stored on an uneven or tilted surfaceTilting lets oil migrate into places it shouldn't during operation or storage.
- PossibleWorn piston rings or valve sealsOn older units, this lets oil into the cylinder continuously, producing ongoing smoke and oil consumption.
- PossibleAir filter oil migrating into intake (on foam-filter engines)An over-oiled foam air filter can be drawn into the engine and burned, producing white smoke.
What to do
- Shut down the generator and let it cool if you notice ongoing smoke rather than continuing to run it.
- Check the oil level once cool and drain any excess back to the correct fill mark.
- Confirm the generator sits level during operation and has been stored upright, not tilted.
- If it has a foam air filter, check that it isn't over-saturated with oil, and re-oil it lightly per the manual if you service it.
- Restart and watch whether smoke is only at startup (often clears as excess oil burns off) or continuous.
- Continuous bluish smoke under normal oil level and level operation points to internal engine wear.
- Persistent smoke from worn rings or seals means the engine needs professional evaluation, since it will keep consuming oil and could eventually fail.
Tools and parts
- Rag
- Oil for correcting level
Small engine oilSearch: “SAE 30 small engine oil”
When to call a pro
Ongoing blue smoke from internal engine wear should be evaluated by a small-engine shop to weigh repair against replacement.
Safety
Use caution
Shut the generator down and let it cool before inspecting; never run a smoking engine indoors or in an enclosed space.