That Old plug looks rusty to me. Does your glow igniter make the plug glow bright red/white hot? Then check the fuel system, refer to my post to see how to do this.
For the igniters, use this to enter the details and work out charge time:
http://www.csgnetwork.com/batterychgcalc.html
Also test your priming system is working. Remove (and clean, and re-oil the air filter), take the glow igniter out, turn everything off, and open it wide open throttle (the...
You've got a leak in the fuel system. Just replace fuel lines, they're most likely stretched and gummed up, check or replace the seal in the fuel tank, and check the fuel filter for air leaks if you have one.