Why will my Honeywell Generator not start?

My 9500 E generator wont start and I am waiting to take it into the shop as a last resort. I started it a few days ago and it fired right up, ran for about a minute, then puttered out. I changed the oil, drained the gas, put in new gas, cleaned the spart arrestor, fully charged the battery and checked the air filter. Everyting is pristine, but now it won't turn over, It tries and tries but never fires up. There are no banging, popping or odd sounds, it just cranks and cranks but never starts. I tried both the pull start and the battery start and they both do the same thing. The fuel line isnt clogged and the spark plug is fine. I have waited a day thinking I flooded it, but when I go back to it it just does the same thing. Nothing seems frozen or locked, it just doesnt want to work. What am I forgetting, of and I am making sure the choke is on and the fuel line is open. Any ideas what the problem may be?