With only the one check valve, it must supply both circuits, that's a different carb model than is usually found on these saws, have seen it on some of the newer Homelites. One less check valve is a good thing. I have seen a lot of strange ways to find the purge tubing routed, usually they are just backwards but this is a new one and surprisingly it should work well as the check valves in the purge bulb are both pointing in the right direction. Not good though, as the fuel pump will have to suck fuel through it during normal running and it will just become another restriction and possible source of air leak in the fuel line. You are right about the way it should be hooked up.