Fuel Systems
INHIBITING OF PETROL INJECTION
METERING UNITS

SI/FS/17
(May 1970)

All metering units are inhibited (flushed out) during production to
avoid possible rusting and seizure of the finely finished moving
parts. However, after a period of 12 months shelf-life, units must
be re-inhibited.

To inhibit a metering unit it must be thoroughly flushed out with
inhibiting fluid, which is injected under pressure (100 psi) (689.5kN/M2)
into the unit while the rotor is being turned. This can be done
on a diesel or nozzle test rig by connecting the rig fluid pipe to the
metering unit inlet union. (A female 0.375" BSP fitting is necessary
for making this connection)

SUITABLE INHIBITING FLUIDS

(1) Fawley White Spirit '100', to which has been added Santolene
'C' in the ratio of 50 parts per million.

(2) Shell Calibrating Fluid 'C'

NOTE: If inhibition is not carried out at the recommended intervals, it
is possible for the shuttle to seize in the rotor, and thus prevent the unit
from 'injecting'.

TO OBTAIN RATIO OF 50 PARTS PER MILLION

1 cc of Santolene 'C' to 5 gallons of Fawley White Spirit.

1cc is equal to 20 drops (0.05cc per drop) from a medicine dropping
bottle or a half-teaspoon. A ratio slightly more that 50 parts per
million would not be harmful.