Symptoms
- Pull cord feels normal but engine never fires
- Engine turns over but dies immediately
- No response at all when pulling starter cord
- Smells strongly of gas when pulling
Likely causes
- CommonStale or old fuelGas older than 30 days breaks down and won't ignite well, especially with ethanol blends.
- CommonFouled or wet spark plugCarbon buildup or flooded fuel on the plug tip prevents a spark.
- PossibleClogged air filterA dirty filter starves the engine of air needed to start.
- PossibleGummed-up carburetorOld fuel leaves varnish deposits that block small carburetor passages.
- Less commonBad ignition coil or spark plug wireElectrical failure means no spark is ever produced.
What to do
- Check the fuel; if it's more than a month old or smells sour, drain it and add fresh gas mixed to the correct ratio for a 2-stroke engine.
- Remove the spark plug, inspect it for black soot or wetness, and clean or replace it with the correct gap set.
- Pull the cord a few times with the plug out to clear excess fuel if flooded, then reinstall the plug.
- Remove and clean or replace the air filter if it's dirty or oil-soaked.
- Check the primer bulb; if it's cracked or won't draw fuel, it needs replacing.
- With fresh fuel, a clean plug, and choke set correctly, try starting again following the engine's warm/cold start sequence.
- If it still won't start, the carburetor may need cleaning or rebuilding by a small-engine shop.
Tools and parts
- Spark plug wrench
- Fresh 2-stroke fuel mix
- Wire brush or sandpaper
- Air filter (spare)
Small engine spark plugSearch: “trimmer spark plug replacement”
Air filterSearch: “string trimmer air filter”
Carburetor rebuild kitSearch: “trimmer carburetor kit”
When to call a pro
If fuel, plug, and filter are all fine and it still won't start, take it to a small-engine repair shop for carburetor service.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.