miker

Hi Mike - got no experience of this one, I know the 335/338 have similar settings. Have you tried the settings? the H setting won't have much of an effect on starting as the L screw controls most of this area. Have you tried starting it with the throttle wide open - it could be the fast idle is coming off when the choke is opened! It sounds like the saw is popping and if it isn't going after that, you are not getting enough fuel through for ignition and that can be down to the fast idle mechanism or lack of fuel.

You won't do any harm by undoing the H screw 3 turns but if it should be 1 turn, it will smoke and flub at high revs.

Good luck

Steve