TOHATSU MFS 25d Service Manual

2-16
Service Data
4st 25/30 2022
6. Maintenance Data
Description Item Standard Value
Engine Parts
Engine
Compression pressure (reference value)
Note) After warming up, remove all the spark
plugs and injector connectors, then
take measurements with the throttle
fully opened.
With Decompression: 0.50 MPa
Without Decompression: 1.40 MPa
Valve (IN/EX)
Valve Clearance
IN: 0.10 - 0.15 mm (0.0040 - 0.0060 in)
EX: 0.20 - 0.24 mm (0.0080 - 0.0094 in)
Valve Stem Outer Diameter
,1ѮPPLQ
(;ѮPPLQ
Valve Stem Runout
-
-
Valve Guide Inner Diameter
,1ѮPPLQ
(;ѮPPLQ
Clearance Between Valve Stem and Guide
IN: 0.008 - 0.040 mm (0.0003 - 0.0016 in)
EX: 0.025 - 0.057 mm (0.001 - 0.0022 in)
Valve Seat Contact Width
IN: 1.0 mm (0.04 in)
EX: 1.0 mm (0.04 in)
Valve Spring
Free Spring Length
IN: 32.85 mm (1.2933 in)
EX: 32.85 mm (1.2933 in)
Rocker Arm
Rocker Arm Inner Diameter ѮPPLQ
Rocker Arm Shaft Outer Diameter (Arm Sliding Part) ѮPPLQ
Clearance Between Rocker Arm and Shaft 0.006 - 0.035 mm (0.0002 - 0.0014 in)
Piston
Maximum outer diameter
Outer diameter at 10 mm (0.3937 in) above
the lower end of the piston skirt
At right angle to the piston pin
ѮPPLQ
Clearance Between Piston Diameter and
Cylinder Inner Diameter
0.020 - 0.055 mm (0.0008 - 0.0022 in)
Adhesion of Carbon on Piston Crown and
Ring Groove
-
Clearance Between Piston Ring and Ring
Groove
Top Ring: 0.03 - 0.08 mm (0.0012 - 0.0031 in)
Second Ring: 0.02 - 0.06 mm (0.0008 - 0.0024 in)
Oil Ring: 0.03 - 0.13 mm (0.0012 - 0.0051 in)
Piston Pin Hole Inner Diameter ѮPPLQ
Piston Pin
Pin Outer Diameter ѮPPLQ
Clearance Between Piston Pin and Pin Hole 0.002 - 0.012 mm (0.0001 - 0.0005 in)
Piston Ring
Ring End Gap
Note) Measure the Ring End Gap at the
bottom of the cylinder bore where there
is little wear if you do not have a ring
gauge.
Top Ring: 0.13 - 0.25 mm (0.0051 - 0.0098 in)
Second Ring: 0.35 - 0.50 mm (0.0138 - 0.0197 in)
Oil Ring: 0.20 - 0.70 mm (0.0079 - 0.0276 in)
Cylinder Head
Cam Bearing Inner Diameter
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ѮPPLQ
ѮPPLQRUPRUHQRFRQWDFW
#3 - oil pump: 33.500 - 33.550 mm (1.3189 - 1.3209 in)
Distortion or Damage on Mating Surface Distortion: 0.05 mm (0.002 in) or less
Carbon Adhesion in Combustion Chamber -
Cooling Water Passage Clogged -

TOHATSU MFS 25d Specifications

General

Brand	TOHATSU
Model	MFS 25d
Category	Outboard Motor
Language	English