Tohatsu MFS 30 [162/319] Power unit

Tohatsu MFS 30 [162/319] Power unit
5-46
Power Unit
25/30 2006
24) Inspection of Piston Outer Diameter
1. Measure piston outer diameter between points specified.
Replace if the diameter is less than specified value.
Piston Outer Diameter a : Standard Value
60.96 mm ( 2.4000 in )
Measurement Points b :
9mm ( 0.35 in ) above piston skirt bottom
Functional Limit :
60.90 mm ( 2.3976 in )
a
b
d
e
a
b
c
25)
Inspection of Cylinder Inner Diameter
1. Measure cylinder inner diameters (D1 to D6) at a, b and c
in crankshaft directions d (D1, D3 and D5 respectively), and
in crank web directions e (D2, D4 and D6 respectively).
2. Obtain taper through calculation described below. Replace
cylinder block if taper is over specified value.
3. Obtain out-of-roundness through calculation described
below. Replace cylinder block if out-of-roundness is over
specified value.
Piston Clearance :
0.020 to 0.055 mm ( 0.00079 to 0.00217 in )
Functional Limit :
0.150 mm ( 0.00591 in )
26) Inspection of Piston Clearance
1. If piston clearance is over specified limit, replace cylinder
block, piston and piston rings as a set, or both.
Note : Measure at the maximum wear points.
Cylinder Inner Diameters (D1 to D6) : Standard Value
61.00 mm ( 2.4016 in )
Functional Limit :
Replace if over 61.06 mm ( 2.4039 in ).
Taper :
D1
D5 ( Measurement Point a )
D2
D6 ( Measurement Point c )
Functional Limit :
0.08 mm ( 0.0032 in )
Out-of-roundness :
D2
D1 ( Direction d )
D6
D5 ( Direction e )
Functional Limit :
0.06 mm ( 0.0024 in )
a 15mm ( 0.6in )
b 35mm ( 1.4in )
c 55mm ( 2.2in )
MFS25_30_ch05.qxd 06.3.9 4:49 PM ページ 46

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