0387593 EVINRUDE PISTON,Std.

Illustration 1 g00294082
(1) Valve springs Length of the valve springs under test force ... 35.8 mm (1.40 inch) Test force of the valve springs: ... 176 to 195 N (40 to 44 lb) (2) Valve spring recess (3) Valve guides Inside diameter of valve guide ... 9.51 to 9.56 mm (0.374 to 0.376 inch) Outside diameter of valve guide ... 15.90 to 15.91 mm (0.625 to 0.626 inch)Overall length of valve guides Inlet ... 57.94 mm (2.281 inch) Exhaust ... 61.10 mm (2.406 inch) Projection of the valve guide above the valve spring recess (2) ... 15.10 mm (0.595 inch)Note: When new valve guides are installed, new valves and new valve seat inserts must be installed. The valve guides and the valve seat inserts are supplied as partially finished parts. The unfinished valve guides and unfinished valve seat inserts are installed in the cylinder head. Then, the guides and inserts are cut and reamed in one operation with special tooling. This procedure ensures the concentricity of the valve seat to the valve guide in order to create a seal that is tight. Refer to the Disassembly and Assembly Manual for removal and installation procedures. (4) Exhaust valve stem Diameter of the exhaust valve stem ... 9.43 to 9.46 mm (0.371 to 0.372 inch)Clearance of valve in valve guide ... 0.05 to 0.13 mm (0.002 to 0.005 inch)Overall length of the exhaust valve ... 123.07 to 123.57 mm (4.845 to 4.865 inch) (5) Inlet valve stem Diameter of the inlet valve stem ... 9.46 to 9.49 mm (0.373 to 0.374 inch)Overall length of the inlet valve ... 122.66 to 123.07 mm (4.829 to 4.845 inch) (6) Exhaust valve face angleNaturally aspirated engine Valve face angle ... 45 degrees Valve seat angle ... 46 degreesTurbocharged engine Valve face angle ... 30 degrees Valve seat angle ... 31 degrees (7) Diameter of the exhaust valve head ... 37.26 to 37.52 mm (1.467 to 1.477 inch) (8) Diameter of the head of the inlet valve ... 44.86 to 45.11 mm (1.766 to 1.776 inch) (9) Angle of the face of the inlet valveNaturally aspirated engine Valve face angle ... 45 degrees Valve seat angle ... 46 degreesTurbocharged engine Valve face angle ... 30 degrees Valve seat angle ... 31 degreesThe valve lash is the following value when the engine is hot or cold: Inlet valves ... 0.20 mm (0.008 inch) Exhaust valves ... 0.45 mm (0.018 inch)
Illustration 2 g00809016
Recess for the valve seat insert (10)