my plugs are new and gone black.looked at carb theirs a grey cap over mixture screw. is it clockwize to weaken and a/cw to richen mixture?im going to have c/o checked fitted a new air filter. c/o at idle should be 1.0 plus a o.50 says haynes. with it being manny choke i think plugs will be black with use of that choke i think. anyone correct me on these items.