I hope somebody at this forum can help with this two-stroke engine problem. Always-starts-on-first-pull McCullough 3214 chainsaw now quits after short (2-3 sec) run. It is *not* just running on prime fuel as it will do this pull after pull. Could this be a bad magneto? Prior to this problem I carefully replaced leaking fuel lines and bypassed rotted-out primer bulb. Now prime with a few drops of fuel directly into carb. Have tried tying off the primer line to upstream end of carb venturi...no go this way either. Solutions, ideas or direction to other resources greatly appreciated. Jim