In my experience, Sea Foam is more suited to diesel engines. I've used it in mine a time or two. Sta-Bil is probably better for gasoline (use that in my boat).
Did you put the SeaFoam in the tank or fill the carb with it?
If you can get the engine started (wire the choke open and crank with the throttle full open), you should be fine. You'll probably rid the neighborhood of mosquitoes for a little while.
