zeroskater58
ArboristSite Lurker
so ive been going through this ms660, and have replaced the crank seals, impulse line, and piston and cylinder on it. i also swapped out the carb, had a cheap chinese carb on it that the high needle would do nothing on so it pretty much would always want to run lean, or flood. i swapped the carb with a tillotson, cant remember the model number off the top of my head. after replacing the carb, it started surging, a little tiny bit at idle, not bad, but at WOT its surging pretty good, to the point it makes it almost impossible to tune. the idle speed screw does almost nothing for it as well, barely barely will get the chain moving screwed all the way in. what do you all think the issue is? my gut tells me fuel lines and/or pickup body, but wanted to see what you guys thought before i take it into the shop. thanks!