My sister just inherited a 350 warrior from her mom. It's been sitting for 5 years and won't run. So me and my dad took it and started working on it, got it to run, but not without the choke on. When the choke is on, it idles very rough - backfiring, poping from the intake - and when the choke is off, it just dies. when its idling with the choke on, when given gas, it dies. any ideas?