Yanmar BY Series Service Manual page 107

Camshaft and Timing Gear Train
12/05
2. Loosen one bolt (Figure 5-76, (1)).
Note: One bolt must be loosened prior to
rotating No. 1 piston to TDC position.
Figure 5-76
Figure 5-76
3. Rotate the crankshaft in the normal running
direction until No. 1 cylinder is at TDC of the
power stroke. The front lobe of each camshaft
(Figure 5-77, (1)) will be facing toward the
exhaust side and the timing marks
(Figure 5-77, (2)) will meet.
Figure 5-77
Figure 5-77
BY Service Manual
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© 2009 Yanmar Marine International
4. Verify position by checking the camshaft timing
marks (Figure 5-77, (2)) on gears are aligned.
The single mark on intake camshaft gear must
fall between the two marks on the exhaust
camshaft gear. NOTICE: NEVER rotate the
crankshaft backward. If the crankshaft is turned
past TDC, rotate two more turns (720°) to bring
No. 1 piston back to TDC.
5. Secure crankshaft in TDC position with flywheel
holding tool OEM No. 11 5 180 (Figure 5-78).
Figure 5-78
Figure 5-78
6. If camshaft is not in alignment, loosen two
remaining bolts (Figure 5-79, (1)) to adjust.
Figure 5-79
Figure 5-79
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