Yanmar BY series, Service Manual

Page: 83 / 275

ENGINE
5-28
BY Service Manual
Cylinder Head
Cleaning Cylinder Head Components
Thoroughly clean all components using a
non-metallic brush and an appropriate solvent.
Each part must be free of carbon, metal filings and
other debris.
Pressure Testing Cylinder Head
1. Remove and disassemble cylinder head. See
Disassembly of Cylinder Head on page 5-26.
Figure 5-25
Note: Special tool OEM No. 11 6 407 consists
of fourteen screws for mounting special
tools 11 6 401 to cylinder head. If
11 6 407 is not available, use the old
cylinder head bolts to secure special
tools No. 11 6 401 and 11 6 402.
2. Seal off all coolant openings using special tool
OEM No. 11 6 400.
Figure 5-26
Note: Reduce surface tension of water used for
test with a few drops of detergent.
3. Connect air source to cylinder head and
immerse in water bath. Apply pressure and
adjust to 4.5 bar (65 psi)
(Figure 5-26) .
4. Inspect cylinder head for discharge of bubbles
indicating a crack in the casting.
Inspection of Cylinder Head
Components
Clean all gasket material, sealant, and carbon from
components. Use a suitable solvent and a
soft-bristle brush to clean parts.
Visually inspect parts. Replace any parts that are
obviously discolored, heavily pitted or otherwise
damaged. Discard any part that does not meet its
specified limit.
A
WARNING
FUME / BURN HAZARD!
• Always read and follow safety related
precautions found on containers of
hazardous substances like parts
cleaners, primers, sealants and
sealant removers.
• Failure to comply could result in death
or serious injury.
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