Product Manual

Parameter Specification
Valve face width (intake and exhaust) 1.0 mm (0.04 in.)
Valve face width (service limit) 2.0 mm (0.08 in.)
Valve margin thickness
Intake 0.55 mm (0.0217 in.)
Exhaust 1.00 mm (0.0394 in.)
Valve seat width 1.0 mm (0.04 in.)
Valve guide bore
Intake and exhaust 5.51 mm (0.217 in.)
Intake valve guide bore (service limit) 5.55 mm (0.218 in.)
Exhaust valve guide bore (service limit) 5.57 mm (0.219 in.)
Valve stem to valve guide
clearance
Intake
0.008–0.04 mm
(0.0003–0.0016 in.)
Intake (service limit) 0.07 mm (0.0028 in.)
Exhaust
0.025–0.057 mm
(0.001–0.0022 in.)
Exhaust (service limit) 0.1 mm (0.004 in.)
Rocker arm shaft outside diameter 12.99 mm (0.511 in.)
Rocker arm shaft outside diameter (service limit) 12.94 mm (0.509 in.)
Rocker arm inside diameter 13.01 mm (0.512 in.)
Rocker arm inside diameter (service limit) 13.05 mm (0.514 in.)
Rocker arm shaft clearance
0.006–0.035 mm
(0.00023–0.0014 in.)
Cylinder head upper camshaft bearing inside diameter
17.975–17.990 mm
(0.7077–0.7083 in.)
Oil pump camshaft bearing inside diameter
15.965–15.980 mm
(0.6285–0.6291 in.)
Valve stem seal color
Intake Black
Exhaust Green
Cylinder Head
90-8M0125265 eng NOVEMBER 2017 © 2018 Mercury Marine Page 4B-3