[alanmcorcoran]

How long has it been since it was last running? If it has sat a while, see all the other threads on this topic. If it were me, I'd let it run for ten minutes or more without touching the throttle and then I'd experiment to see if really hitting it worked or if gently increasing it worked. Also, you don't mention what you are doing re choke. You might need to choke it all the way for the first few minutes - or longer.

In many cases, you can cure I've-been-sitting-around-a-while-itis by just cajoling a tankful of gas through the carb. If it's been sitting a while, this can take some patience and experimentation with the choke and the throttle.

There's a host of other issues (crap in the tank, crap in the carb, bad plug, bad petcock, broken vacuum hose, clogged air filter, bad float, bad gas, etc.) that this won't fix - but this is the most common problem encountered with the GZ.

Good luck - let us know how it comes out.