Chainsaws

Purchased Poulan Pro Chainsaw PP3516AVX in 09/13. Using around home for shrub and root removal (careful not to touch ground) -- no trees or log cutting. Having difficulty restarting after it is warmed up. Will not restart even after closing choke and clearing flood. Sometimes after a start, chain will race around bar without having pulled on trigger. Chainsaw will stall if not keeping a level cut, ie, tilting saw up or down within 45 degrees.
Any suggestions?