I'm left wondering how the 620 carb can help a 590 when the 590's OEM carb (without modification) seems so rich you couldn't lean too much if you wanted to, wouldn't this kinda imply the carb is more-than adequate?
I wish youtuber 'Tinman's Saws' compared a stock 590, to a muff-modded 590-- he does a comparison only between a stock 590, then the same 590 with muff-mod and the 620's carb&coil....really curious what % each of these is making towards the results he gets!
Has anyone actually posted "OEM timing-#'s for the stock 590, and stock 620, cylinders"? Had thought the 620 cylinder was same, just the piston having some minor differences, but upon rewatch of the echo-youtube channel their rep clearly says the 620 has better timing **and** porting..
Re "620p has better timing, because of the coil....so spend $100 on the coil so your 590 runs harder"..... Because coil-firing is a once-per-revolution thing, aren't we literally talking about 1 number (ie the degrees-of-timing before TDC that the plug is fired, how many degrees advanced before TDC it fires), I cannot stop thinking that one could obtain identical results by either swapping to a 620 coil OR simply filing the keyway in their 590's flywheel to match a 620's stock-timing. VERY eager to learn this one, thanks a lot for any insight!!!
Gotta wonder how big a gain that 620 carb is giving (both on stock590's and ported590's), my understanding was this same carb(590's) is the one used on the 67cc CS-670 so it's hard thinking it can't provide adequate fuel/air charge for the engine..