I have a cheapo homelite bandit chainsaw that is giving me some headache. The saw refuses to idle without reving the engine. If I set it down, the saw will die. Other than that, it cuts fine. I see a couple of adjustment screws on the side but I don't have a manual to know how to adjust them. There is a 'T', 'L', 'H' adjustment. Which way and which one should I mess with?