If the mixture screw is wound fully in, that is fine.......it indicates there is either too much air bypassing the slide, or even a possible leak at the carb to manifold slip joint..........If it's an old carb, and the slide is a number 4 then it will almost certainly be too much ware in the slide/bore.......Now if the mixture screw was initially wound out from this, the mixture at idle would be too lean.......in which case if the mag had a weak spark when hot, then there is your hard starting issue........So my advice is to also look at the carb if you really want to tune the engine properly.........generally on the 229/289 carby's these days a number 4 slide is on the lean side anyway.