5-4. MAIN PROPULSION ENGINE/MARINE GEAR - REMOVAL AND RUN-IN
MAINTENANCE INSTRUCTIONS. (Continued).
RUN IN (Cont)
The restriction at this point should be checked at a specific engine speed.
Then the air cleaner and ducting should be removed from the air inlet
housing and the engine again operated at the same speed while noting the
manometer reading. On turbocharged engines, take the reading on the inlet
side of the turbocharger. The difference between the two readings, with and
without the air cleaner and ducting, is the actual restriction caused by the air
cleaner and ducting.
Check the normal air intake vacuum at various speeds (at no-load) and
compare the results with the Engine Operating Conditions in Chapter 3.
Record these readings on the Engine Test Report.
Check the exhaust back pressure (except turbocharged engines) at the
exhaust manifold companion flange or within one inch of this location. This
check should be made with a mercury manometer through a tube adaptor
installed at the tapped hole. If the exhaust manifold does not provide a 1/8"
pipe tapped hole, such a hole can be incorp rated by reworking the exhaust
manifold. Install a fitting for a pressure gage or manometer in this hole. Care
should be exercised so that the fitting does not protrude into the stack. On
turbocharged engines, check the exhaust back pressure in the exhaust
piping 6" to 12" from the turbine outlet. The tapped hole must be in a
comparatively straight area for an accurate measurement. The manometer
check should produce a reading in inches that is below the Maximum
Exhaust Back Pressure for the engine
Turbocharger compressor outlet pressure and turbine inlet
pressures are taken at full-load and no-load speeds.