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20
Fuel system
The pump unit
Pumps fuel from the tank to the carbu-
rettor.
Dismantling the carburettor
Remove the control diaphragm and
check for damage.
Replace if required.
Pressure test the metering unit.
531 03 06-23
The pump unit
This is where the pump diaphragm (E)
that pumps fuel from the tank to the
carburettor's measuring unit is found.
The diaphragm is affected by pressure
variations in the engine's crankcase via
an impulse channel (F).
If the channel is blocked, by grease or a
wrongly facing gasket, for example, the
pump unit does not function and the
engine cannot be started.
Dismantling the carburettor
Carefully remove the control dia-
phragm (A) and gasket (B).
Check the diaphragm for holes and
wear on the pin (C).
Replace the diaphragm if required.
Connect pressure tester 531 03 06-23
to the fuel hose nipple.
Lower the carburettor in a vessel with
petrol in order to discover any leaks
more easily.
Test the pressure at 50 kPa.
No leakage is permitted.