To make the engine start, here's what I do:
1. Pump gas pedal one time. Remove lid from air cleaner. Ensure that choke is closed

GOOD - choke closed all the way



WRONG - choke not closing all the way



If it doesn't close all the way, it won't start in cold weather. See Choke Adjustment

2. Refit lid to air cleaner. Squirt two puffs of Starting Fluid into air cleaner snorkel

3. Turn key to START until engine is running

Starting Fluid guarantees that the engine has fuel regardless of fuel pump, fuel pressure, or carburetor. So it will fire/catch (although it may not stay running) - we've even used it on engines where the carburetor is removed. If you use Starting Fluid and there is no Fire, it indicates the Spark is bad and should be checked