Iran Tractor ITM 470, Инструкция для оператора

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4
Maintenance and adjustment
72
Removing air from the fuel system
If at any time air enters the fuel sys-
tem, either due to fuel system servicing,
running out of fuel, tractor standing idle
for a considerable time or difficulty with
starting, the following procedure must be
used to remove air from the system:
NOTE
If air removal temporarily eliminates
the problem, but it occurs again, you
must fully check and test all fuel lines
and connections. Loose fuel connections
and gasket surfaces, or damaged fuel
lines, can allow air to enter the system
without showing any apparent leakage.
With a clean unrestricted element, air
leaks will usually occur on the suction
side of the system between the fuel tank
and the fuel lift pump. With a badly re-
stricted fuel filter element installed, the
transfer pump portion of the injection
pump (in its attempt to obtain fuel) may
also pull air into the system. Retighten,
but DO NOT overtighten, all fuel connec-
tions and replace the fuel filter element
as necessary.
Fuel filter (Fig. 20)
1. Slacken the outlet union (1 Fig. 20) on
the primary fuel filter.
Fig. 20:
1
2. Operate the hand priming lever (1 Fig.
21) on the fuel lift pump until fuel, free
of air bubbles, issues from the union,
then retighten the union.
NOTE
If the drive cam of the fuel lift pump
is at maximum lift, it will not be possi-
ble to operate the priming lever. In this
situation, the crankshaft must be turned
one revolution.
Fig. 21:
Fuel injectors and thermostart
3. Slacken the unions at numbers one and
three fuel injector.
4. Slacken the thermostart fuel feed pipe
(Fig. 22) at the thermostart and oper-
ate the fuel lift pump until fuel, free of
air bubbles, issues from the pipe, then