Hi Patrick:
Since it's running we'll assume that the ignition side is OK, so the next thing to check is fuel delivery.
I'd be draining and flushing the carb, make sure there is fresh gas in the tank, if there is a fuel filter think I'd clean or replace it, make sure the air filter is clean, and then give it another go.
Let me know how you're progressing by comment on this post.
Cheers.