Technical data

34
2003T Turbo Compressor
Where there is an excessive amount of smoke in the
exhaust fumes or the engine output is particularly low
it may be that the turbo is not functioning properly. If
the boat’s speed through the water is gradually de-
creasing, the boat’s bottom should also be inspected,
and cleaned where necessary. Check that the air in-
take has not become clogged, and clean the intake
silencer. Messure the supercharging pressure under
full load at 3200 rpm. The boost pressure should be
100 kPa – 120 kPa (14.5 – 17.4 psi) at 20°C (68°F).
NOTE! It is important to maintain full loading long
enough to enable the pressure to stabilise if results
are to be correct. Also note that the pressure varies
with the temperature of the intake air, as shown in the
diagram below. The supercharging pressure is given
at +20° (68°F), which implies that the measured
pressure must be corrected as shown in the diagram if
the intake air is not at this temperature when the
measurement is made.
1. Inspecting the Seals
Check the joints between the turbine housing and the
compressor bearing housing, and between the com-
pressor bearing housing and the compressor housing.
2. Checks
Check the pre-injection angle, the injector’s opening
pressure and the spray pattern. The valve clearance
and compression should also be checked.
Maximum permissible radial clearance: 0.17 mm
(0.00669 in).
If wear and tear has reached the maximum permissi-
ble the turbo-compressor should be reconditioned or
replaced.
Turbo compressor
Boost pressure at various pressures
A. Boost pressure measured
B. Correction graphs
C. Intake air temperature (IAT)
Example:
A pressure of 100 kPa recorded at 0°C is the
equivalent of 92 kPa at +25°C.
3. Checking axial and radial clearance
Dismount the turbo-compressor from the engine, and
measure the rotor unit’s axial and radial clearance.
Maximum permissible axial clearance: 0.09 mm
(0.00354 in)