Guys, Im in need of some help. I let my 2002 450 s set up for too long and wound up with a stuck float. This thing was running like a scalded dog when I put it away, but a move put a kabosh on any riding for a while so shame on me I know….

Heres what I did:
1. Took carb apart replaced jets, cleaned out
2. Drained the gas tank and filled it up with fresh gas.
3. I set the pilot screw to 2 1/2 turns out from lightly seated.
4. Changed Spark Plug.

Now when I start it (1/2 choke) it seems to run great……. when I close choke completely and try and give it gas it kills the engine. This goes on for about 5 min. Once its warmed up if I hit the throttle and rev it up I get a little back fire on the way up and a poo inducing gunshot like backfire on the way down. After a hearing test and a change of drawers (AKA 5 minutes or so later running at idle) It revs up and comes back down with minimal indication anythings wrong. Ive also notice that if I pull choke out completely the engine revs up high but with some audible popping from the exhaust. I pulled the plug after riding for a few hours and the strap above the electrode is white/gray. My problem is that it takes a while to warm up even on a warm day, which it didnt seem to need before the carb clean. The throttle killing the engine is new, and the backfiring on rev down is new. Any ideas on what to adjust and where. I suck as a mechanic and hope yall can help me get this thing running like she was.

Thanks.