81 OMC sterndrive 800 with 305. Been parked for 4 years. Previous owner says no problems when parked. First attempts at running with hose attachment no water at all. Replaced impeller via dropping lower. Now I have water at " pee hole" but no water at hose from intermediate at idle. Increase to 1500 rpm and get good flow at hose but stops when returning to idle. Any help appreciated. Also have greased zerk.