1979 Evinrude 4 HP Outboards Service Manual, PN 5424, Page 24Get this manual
LEAF VALVES aInspect the leaf valve assembly and disassemble if necessaryThe leaf valves must be free from all varnish and gum, and the leaves must be perfectly flat and without distortion so that they form perfect seal with the leaf plate baseSee Figure 3-12bDO NOT attempt to bend or repair damaged leaf; replace the complete assembly if damagedDO NOT under any circumstances bend or flex the leaves by handcReplace the broken leaf stop if any leaves are
CORE PLUGS aIf leakage occurs at core plug area, smart tap with hammer and flat end punch in the center of the core plug will normally correct this condition See Figure 3-13If necessary, remove core plug to clean out slow speed orifice holesSee Figure 3-14
dClearance under leaf stop should be 14" (6.35 mm); adjust if necessary by bending leaf stopSee Figure 3-12
1Leaf plate
2Leaf valve 3Leaf stop