Model 720r hard starts, then dies within 10 seconds. It is used, and holes are drilled in case to access carb screws. Found wrong spark plug size, but I need to know how to reset carb screws, in a non running condition. I'm thinking because of holes, screws have been adjusted all over the place, and that might be causing problems, thought I haven't yet tested compression.
In my expierence you turn the screws in gently until they stop then out 1 and a half to 2 turns this is the base setting and you adjust them more accurately when its running from there. one sacew is the low rev setting marked L and the other is high rev setting marked H. in is leaner or less fuel and screwing it out means richer more fuel . Hope this helps