Engine starting problems have a few common causes, especially if you’re using your lawn mower or outdoor power product after it’s been stored for the winter or off-season.
Safety Tip: ALWAYS remove / disconnect the spark plug before performing engine repair. check this out: http://www.create-baby-stuff.com/lawn-mower-safety/
Step 1: Check Your Fuel
Do you have fresh, clean fuel in the tank? If it’s empty, fill it up and go! If it’s full, check that the fuel shut-off valve is open and that it is clean.
Fuel needs to be stored in a suitable container . Stale fuel, dirt and debris are the most common cause of outdoor power equipment not starting properly. If you store equipment with untreated gas in the tank, it can lead to engine damage.
Step 2: Clean the Carburetor
Carburetor Problems Cause Mower Engines Not To StartThe carburetor regulates how air and fuel move through the engine to power your equipment. If the carburetor is dirty, that can cause poor engine performance or starting problems.
>> Follow these steps for cleaning carburetors
>> Follow these steps for carburetor rebuild
Step 3: Check the Spark Plug & Possible Ignition Problems
Disconnected, dirty or fouled spark plugs are common causes for engines that won’t start. Spark plugs typically need to be replaced every season or 25 hours of use. You should also check that the spark plug gap is set properly.
>> Follow this guide on checking and replacing spark plugs.
If your spark plugs look good, problems with your ignition system can also preventing a spark. These can range from a faulty spark plug lead, shorted kill switch or flywheel key damage.