Chainsaw Won't Start

A chainsaw that won't start usually has a fuel or carburetor problem. Two-stroke engines are picky about fuel freshness. Start by draining old gas and adding fresh 50:1 mix. If that doesn't work, check the spark plug and air filter. Most starting issues can be fixed in under an hour.

Quick Diagnostic Checklist

  • 1. Check fuel mix — Must be fresh 50:1 (gas:2-stroke oil). Fuel older than 30 days causes 80% of starting problems.
  • 2. Check for flooding — Smell gas at the spark plug hole? Engine is flooded. Clear it before trying again.
  • 3. Inspect spark plug — Should be light tan/gray. Black = rich/flooded. White = lean. Wet = flooded.
  • 4. Clean air filter — Sawdust clogs filters fast. A dirty filter causes hard starting and poor running.
  • 5. Check fuel lines — Cracked or clogged fuel lines prevent fuel from reaching the carburetor.

Chainsaw Repair Guides

Frequently Asked Questions

Why won't my chainsaw start?

Common causes: stale fuel (most frequent), flooded engine, fouled spark plug, clogged air filter, or carburetor issues. Two-stroke chainsaws are especially sensitive to old fuel - use fresh 50:1 mix less than 30 days old.

How do I start a flooded chainsaw?

Remove the spark plug and pull the starter cord 10-15 times to clear excess fuel. Let it sit for 10 minutes. Reinstall a dry plug, set choke to OFF/RUN position, and try starting. If still flooded, you may need to clean the carburetor.

What fuel mix do chainsaws need?

Most chainsaws use 50:1 gas to oil ratio (2.6 oz oil per gallon of gas). Some older models use 40:1. Always use quality 2-stroke oil - never automotive oil. Stihl, Husqvarna and Echo all recommend their brand-specific oils.

Chainsaw Guides by Brand