Yanmar 4BY2, Service Manual, Page: 116 / 248

ENGINE
Camshaft and Timing Gear Train
5-54
BY Service Manual
© 2009 Yanmar Marine International
22. Do not remove loop casting bolts. NOTICE:
NEVER remove bolts retaining loop casting
(Figure 5-101).
Figure 5-101
Figure 5-101
Install Camshafts
1. Lubricate all camshaft bearings, caps and
journals with clean engine oil.
2. Identify the intake (Figure 5-102, (E)) and
exhaust (Figure 5-102, (A)) camshafts.
Figure 5-102
Figure 5-102
3. Install camshafts. Ensure the timing marks
(Figure 5-103, (1)) on the gears align as
shown.
When the timing marks are aligned, the lobes
(Figure 5-103, (2)) for cylinder No. 1 will face the
exhaust side of the engine.
Note: The valves will hold the camshafts above
the bearing seats until all bolts are
tightened.
Figure 5-103
Figure 5-103
Note: Bearing caps are numbered beginning at
the front (Figure 5-104, (1)) of the
engine. The numbered markings of all
caps should face the exhaust side
(Figure 5-104, (2)).
Figure 5-104
Figure 5-104
000 3 77 8
(1)
(2)
000 3 77 9
(2)
(1)
E2
A2A2
E2
E1 E1
A2A
2
A1 A1