1973 4hp evinrude not get fuel to choke it. Carbs are cleaned,fuel is filling up the carb bowl ,needle and seat is in perfect condition,float is level and floating like its suppose to. In having problem with it staying running. The long idle screw at the top of the carb I don't know how many turns I'm suppose to turn it. Also it was choking correctly and running until I took the top long idle screw out and checked the rings that was on it. It had a little white one on the front part of the idle screw about an inch from the pointed part of the idle screw that was it. I took it off and replaced 2 o or gasket rings on the back part of it at the end of the threads so it wouldn't get thread when I put it in. I put the 2 rings on it from what it said on the diagram. Every sense then I'm not getting any fuel when I choke it. I poored gas in the carb it will run for 10 seconds and cut off like its not getting any fuel at idle or maybe getting too much air. I tried all kinds of adjustments like the manual said and its doing the same thing. Please help. Thanks.