Yanmar 4BY - Adjusting Charge Pressure - 4 BY

TURBOCHARGER
9-8
BY Service Manual
Tests and Adjustments
Adjusting Charge Pressure - 4BY
Note: The waste gate control rod on 6BY
engines is not adjustable.
IMPORTANT
NEVER change the length of the wastegate
control rod without doing it in coordination
with a charge pressure test. (See
Measuring Charge Pressure on page 9-7.)
Doing so will cause incorrect boost
pressure resulting in poor performance or
engine damage, and can void all warranty.
Figure 9-2
1. Remove retainer (Figure 9-2, (1)).
2. Loosen jam nut (Figure 9-2, (2)).
3. Turn wastegate control rod connector
(Figure 9-2, (3)) to shorten or lengthen rod.
• Lengthen the rod to reduce charge pressure.
• Shorten the rod to increase charge pressure.
One-half turn will result in a change of
approximately 25 bar (0.4 psi).
One turn will result in a change of approximately
50 - 60 bar (0.70 - 0.8 psi).
4. Install wastegate control rod connector and
secure with retainer. Tighten jam nut.
5. Operate engine under normal load conditions
and verify pressure reading is within
specification. See Measuring Charge Pressure
on page 9-7.
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