Symptoms
- Oil spots or puddle under the equipment
- Oil visible on the outside of the engine casing
- Oil level drops faster than normal between checks
- Smoke or burning oil smell from the engine
Likely causes
- CommonWorn or loose oil drain plug gasketThe gasket seals the drain plug and can wear out or be reused too many times.
- CommonOverfilled crankcaseToo much oil can be pushed out through seals or the breather.
- PossibleWorn crankshaft sealSeals harden and shrink with age, allowing oil to seep past.
- PossibleDamaged valve cover or case gasketGaskets can degrade or be improperly seated after service.
What to do
- Check the oil level and don't overfill; use the dipstick to fill only to the indicated mark.
- Inspect the drain plug for looseness and check the gasket for damage, replacing it if worn.
- Wipe the engine clean and run it briefly to spot exactly where oil is seeping from.
- Check the crankshaft seals at the front and back of the engine for visible oil weeping.
- Inspect visible gaskets on the valve cover or crankcase halves for gaps or damage.
- Tighten the drain plug to the correct torque, not excessively, to avoid stripping it.
- If the leak is from a crankshaft seal or internal gasket, a small-engine shop can replace it.
Tools and parts
- Wrench set
- Drain pan
Oil drain plug gasketSearch: “small engine oil drain plug gasket”
Crankshaft sealSearch: “small engine crankshaft seal replacement”
When to call a pro
A small-engine shop can replace crankshaft seals or internal gaskets if the leak isn't from the drain plug.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.