1997 Johnson Evinrude "EU" 40 thru 55 2-Cylinder Service Manual, P/N 507265, Page 88Get this manual
Assembly
When assembling the fuel piston, always install new washer and stem in addition to other new parts requiredBe sure to lightly tighten stem with fingers; never with pliers[] Lubricate stem with Evinrude or Johnson Outboard Lubricant and slide it into hole in center of intermediate housing
Install new washer on air motor piston screwThen, thread air motor piston onto stem with clockwise rotationPush poppet valve in (toward the stem) to hold the screw in place while turningTighten 1f4 turn past point of contactate housing