If you have a Honda GX engine, when cold, choke and be prepared to back it off slowly. Do all this with the gun depressed. If it pops and stutters with the choke lever actived, take the choke off and with the gun depressed, give it one pull and it should start right up.
Keep the gun depressed and let it warm up before releasing the trigger.
You should have the choke lever completely off while it's running. If you have to slide the choke part way to keep it going, then you may have some trash in the main jet of your carb.
Good luck,
Merrill