Small Engines (Lawn Mowers, etc.): Toro Snowblower - S620 Starting Problems, fuel tank cap, toro snowblower

Question
Hi Ben,
I have an older Toro snowblower that will not start. I had started it with fresh gas and let it run for a few minutes,then shut it down. When I came back out a hour later it would not start. I am getting spark and it has compression. It appears that it is flooding i.e. gas visible in carb well and the gas seems to be draining from the tank into the carb. Is there needle and seat assembly that could be stuck? Also is there a site that shows the exploded view of the carburetor? Your advise would be appreciated!
Kevin  

Answer
Kevin
Problem: Engine will not start or is hard to start.
Possible causes:

Fuel tank is empty or shutoff valve is closed, or fuel line or fuel tank cap vent is clogged.
There is water in the fuel.
Carburetor is overchoked.
Carburetor is improperly adjusted or needs service.
Ignition system or its wiring is defective or ignition switch is off.
Deadman or other cutoff switch is open or defective.
Spark plug is fouled, improperly gapped, or damaged.
Engine compression is poor.
Operator needs to read user manual. :)

Problem: Engine starts easily but dies after a few seconds.
Possible causes:

Fuel tank is empty or shutoff valve is closed, or fuel line or fuel tank cap vent is clogged.
Carburetor is overchoked.
Carburetor is improperly adjusted or needs service.