If however the low speed mixture is too rich (and that is typical of factory settings with these type engines ) it can cause flooding or partial flooding which can make the engine very difficult to turn over. (and it's very hard on the pull start mechanism )

The spitting and sputtering from idle through transition to higher r.p.m. means it's loading up...and the low spd. mix needs leaning out a bit. Turn the low spd. adj. in CW 1/8 turn at a time to sneak-up on it.