- Switch the pump to pressure mode (PRES-
SURE).
- Operate the pump slowly and check if there is an
increase of pressure. A small leakage is consid-
ered to be normal.
If anomalies are detected, replace the pump.
N.B.
A MALFUNCTIONING ONE-WAY VALVE CAN RESULT IN
RUBBER COUPLING AND FILTER OVERHEATING
N.B.
ABSENCE OF VIBRATION INDICATES INEFFICIENT SEAL-
ING
Specific tooling
020329Y MityVac vacuum-operated pump
Inspecting the cut-off
- Remove the SAS valve.
- Connect the MITYVAC pump in low-pressure
mode (VACUUM) to the CUT-OFF valve vacuum
intake.
- Apply a vacuum value higher than 0.5 BAR.
- Check that this value is kept all the time.
- If a worn seal is detected, replace it.
- With a "T" bypass and flexible rubber hoses make
a parallel connection between the rubber coupling
and the vacuum intake of the CUT-OFF valve.
- Connect the bypass to the MITYVAC pump.
- Set the pump set to the low-pressure mode
(VACUUM).
- Using a pair of long flat pliers, choke the rubber
hose next to the valve.
- Operate the pump until vacuum is higher than 0.5
BAR.
- Release the hose and check how the vacuum re-
acts. - Under normal functioning conditions the
vacuum undergoes a slight fall and then readjusts.
There follows a slow and continuous loss of de-
pression up to approximately 0.4 BAR. At this point
MSS X9 Evolution 250 Engine
ENG - 143
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