Symptoms
- Pull cord resists or won't fire the engine
- Engine turns over but doesn't start
- Starts then dies immediately
- Chain brake lever in the forward (engaged) position
Likely causes
- CommonChain brake engagedMany chainsaws won't run properly or safely with the chain brake set.
- CommonStale fuel mixtureOld two-stroke fuel mix degrades and clogs the carburetor.
- CommonFouled spark plugCarbon buildup weakens spark.
- PossibleFlooded engine from over-primingExcess priming floods the cylinder with fuel.
- PossibleClogged air filterSawdust quickly clogs chainsaw air filters.
What to do
- Confirm the chain brake is released (pulled back) before attempting to start.
- Drain stale fuel mix and refill with a fresh two-stroke mixture at the correct ratio.
- Pull the spark plug and check for fouling; clean or replace it.
- Clean or replace the air filter, which clogs quickly with sawdust.
- If flooded, remove the plug, dry it, and pull the cord a few times before reinstalling.
- Check the choke position matches engine temperature (cold vs warm start procedure).
- If it still won't start, the carburetor may need professional cleaning.
Tools and parts
- Spark plug socket
- Two-stroke fuel mix
Chainsaw spark plugSearch: “chainsaw spark plug replacement”
Chainsaw air filterSearch: “chainsaw air filter replacement”
When to call a pro
A small-engine shop can clean or rebuild the carburetor if fuel and ignition checks don't resolve it.
Safety
Use caution
Always engage the chain brake when not actively cutting and keep hands clear of the chain during starting attempts.