Also, when you go to start it, full choke, two quick blips on the throttle, and turn up the idle. You should be able to kick it over, have it start, turn the choke down 1 level when it starts sputtering, turn it down to off when it starts sputtering again, and then let it idle until warm without ever touching the throttle after the two blips.
Turn up the idle!!! When I got mine I took it to the woods and never did get it started. If there was a cliff near by I would have pushed it off with no second thoughts. Also, try a new plug. Put in a new plug and turn up the idle. Never let it sit for more than a day w/o draining the bowl or running it out of gas. I used to curse my 400, but now, even after a whole winter of sitting I can start it with only 2 or 3 kicks. Love it!!!