ENGINE
Inspecting the Cylinder Block and Components
5-22
6LY3 Service Manual
© 2007 Yanmar Marine International
INSPECTING THE CYLINDER
BLOCK AND COMPONENTS
The cylinder block is a light alloy casting machined
with functionally designed ribs and support
structures. The side walls are shaped to maximize
rigidity, strength and quiet operation.
Perform a visual inspection for cracks on engines
that have been exposed to freezing temperatures,
have overturned or been subjected to undue stress.
Perform a dye penetrant inspection on any
suspected cracks. Replace the cylinder block if a
crack is not repairable.
Inspecting Oil Passages and Freeze
Plugs
Clear all oil passages of any obstructions and
ensure that all freeze plugs are secure.
Figure 5-9
Figure 5-9
1 – 65 mm (2.559 in.) Plug
2 – 40 mm (1.574 in.) Plug
3 – 40 mm (1.574 in.) Plug
4 – 16 mm (0.629 in.) Plug
5 – 35 mm (1.377 in.) Plug
6 – Flywheel End
7 – 40 mm (1.574 in.) Plug
8 – 16 mm (0.629 in.) Plug
9 – 40 mm (1.574 in.) Plug
Dye Penetrant Inspection Procedure
The dye penetrant inspection kit consists of an
aerosol cleaner, penetrant and developer.
Figure 5-10
Figure 5-10
NOTICE: Always read the instructions included with
the dye penetrant kit before use.
1. Spray the cleaner directly on the surface to
soften heavily soiled areas or wipe the area
with a cloth moistened with cleaner.
2. When the surface is clean and dry, spray the
penetrant on the suspect area so it is
completely covered and the penetrant liquid
shows a smooth surface tension. Use enough
penetrant to maintain a wet appearance for at
least 10 to 15 seconds. Do not disturb for 5 to
10 minutes.
3. Spray the developer on a clean shop towel and
remove any excess dye penetrant.
4. Spray a uniform thin film of developer on the
remaining penetrant and allow to develop for
several minutes. Cracks will appear as red dots
or a continuous red line on the surface being
inspected.
5. When finished, clean the surface with the
cleaner.
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