i have a poulan pro backpack (BP400) with kawaski motor. it started running like crap lately (wouldnt run without the choke on full or just off full) then wouldnt start at all. one of the gas lines cracked and it was sucking air and leaking gas on the prime. i replaced this but still ran like crap if at all. next notice the other line inside the tank (pickup) was split. replace it and now it runs again but still not like it did before all this started happening. i still have to leave the choke on at least half way. any ideas what to check next? thanks. oh yeah, its about 7 yrs old and until lately ran like a champ.