Two-Cycle Small Engine Start Up Tips

Give your starter-cord arm a rest while you run these basic diagnostic tests

When two-cycle leaf-blowers, string trimmers, chain saws or other small engines won't start, first see if one of these common problems is the cause.

By the DIY experts of The Family Handyman Magazine

Look for fuel or spark plug problems first

Having trouble starting a balky two-cycle leaf blower, string trimmer or chain saw? Here’s what to do.

Check for a spark. If you’ve primed the engine and pulled the cord but still get no sign of life, disconnect the spark plug boot from the plug and insert a paper clip. Hold the rubber boot and move the end of the clip about 1/8 in. from the engine while you pull the cord. Look for a spark to jump the gap. No spark? Take it to a pro.

Check the fuel system. If you have a spark, check the fuel system. Remove the spark plug and examine the tip. If the tip of the plug is wet, the engine is flooded, proving that it’s getting fuel. Perform the drying procedure shown in Photo 1. Then reinstall the plug and try starting the engine again.

Try starting fluid. If the engine isn’t flooded or it still won’t start, try starting fluid. Find the air intake and remove the air filter. Spray a one-second burst of starting fluid into the air intake. Reassemble the filter and try to start the engine. If it still won’t start, that means it’s not getting any fuel. It’s time to take the unit in for professional repair.

Avoid old gas. The major reason for balky engines is old fuel. If your gas is more than a few months old, it’s likely the cause of your starting problems. Get rid of it by taking it to your neighborhood recycling center. Refill your gas can with fresh gas and add a fuel stabilizer. If you’ve been running old fuel through the engine, you may have to take the machine in to remove the varnish from the carburetor.

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Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

  • 4-in-1 screwdriver
  • Air compressor
  • Air hose
  • Rags
  • Socket/ratchet set

You'll also need a blower attachment for the compressor (or canned air) and a paper clip.

Required Materials for this Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here's a list.

  • Starting fluid
  • Fuel stabilizer