Inspection Of Valve; Inspection Of Valve Guide - TOHATSU MFS 9.9 Owner's Manual

Power Unit

13) Inspection of Valve

1. Check valve for dent and wear on the face. Replace if
necessary.
Measure valve stem outer diameter b. Replace if it is less
2.
than specified value.
Valve Stem Outer Diameter b : Standard Value
Intake Side
Exhaust Side : 5.46 mm (0.2150 in)
Functional Limit :
Intake Side
Exhaust Side : 5.44 mm (0.2142 in)
3. Measure valve stem runout. Replace if it is over specified
value.
Valve Stem Runout Limit :
Intake Side
Exhaust Side : 0.03 mm (0.0012 in)

14) Inspection of Valve Guide

Before inspecting valve guide, check that valve
stem outer diameter is within specified limit.
Measure valve guide inner diameter a. Replace cylinder
1.
head if the inner diameter is over specified value.
Valve Guide Inner Diameter a : Standard Value
Intake/Exhaust Side : 5.51 mm (0.2169 in)
Functional Limit :
Intake Side
Exhaust Side : 5.57 mm (0.2193 in)
2. Obtain clearance between valve guide and valve stem by
calculating as described below. Replace cylinder head
and/or valve if the clearance is over specified value.
Clearance between valve guide and valve stem =
Valve Guide Inner Diameter a - Valve Stem
Outer Diameter b :
Intake Side : 0.008-0.040 mm (0.00031-0.00157 in)
Exhaust Side : 0.025-0.057 mm (0.00098-0.00224 in)
Functional Limit :
Intake Side : 0.070mm (0.00276 in)
Exhaust Side : 0.100 mm (0.00394 in)
5-30
: 5.48 mm (0.2157 in)
: 5.46 mm (0.2150 in)
: 0.05 mm (0.0020 in)
: 5.55 mm (0.2185 in)
b
a
b
4st 9.9/15/20 2008