330 magnum 2003 carb issue
 

Trying to get my 330 running right to sell Problem started last winter blading snow running fine then one time started loosing power at about half throttle so I used that way till spring then tore carb apart found main jet had come unscrewed was loose in bowl fixed that got full power back but now every time after starting n running then shutting off won’t start unless drain fuel in bowl I just did a carb rebuild with kit didn’t help also replaced fuel pump earlier Is float setting the problem I messed with fuel mixture setting from 1 to3 turns out no help either

Quick check of float-height setting.
Place a foot-length of clear tubing on the bowl-bottom-outlet. Form a loop straight up alongside the carb. Leave the end open.
Now open the drain screw. Fuel will rise up the tube to the top of the bowl.
It must be even with the bowl-gasket. Not above. Not below.
Do not start the engine. Pump may squirt fuel out the tube. That drain tube also serves as the air-vent to the bowl.

Setting too low = problems starting & low speed. Setting too high = exhaust will stink ! Spark plug will be black. Drips.

You have a chainsaw ? The carbs tune the same. The 'mixture-screw' is 'LOW' The main-jet & needle is 'HIGH'.

I do not understand the issue of draining the bowl, to re-start a warm engine.
My guess is the float is sticking shut. When you completely drain the bowl, it opens.
(There are many issues with 'rubber-tit' float valves. I'm kinda old-school, preferring brass on brass.)

Hope this helps. Post your solution.

I would have to agree, seems like a float/needle/seat issue to me.