1999 "EE" Evinrude 70HP 4-Stroke Service Manual, P/N 787023, Page 77Get this manual
4Squeeze diaphragm and piston between thumb and forefingerto relieve pressure on pinShake pin out or remove it with magnetCarefully allow diaphragm and piston to expand (they're under spring pressure)Slide out diaphragm, two springs, and piston5Inspect both diaphragmsReplace if cut or torn
Reassembly
1Insert large spring into top of valve body and small spring into bottom2Slide diaphragm into top of valve body and piston into bottom49247
3Rotate diaphragm and piston so slot in diaphragm shaft will align with hole in pistonCompress diaphragm and piston with thumb and forefingerInsert pin into piston when slot and hole align, then release pressure on diaphragm and pistonRotate diaphragm (approx90) back into original positionPin should not be visible4Place valve body on diaphragm making sure disassembly marks align and valve body is correctly oriented (valve chamber wall should be up toward upper diaphragm)49248