Table of Contents
11
A
28
DECOMPRESSION VALVE
B
Decompression valve
Function
The decompression valve reduces the compression in the cylinder when
starting.
A limited quantity of fuel/air mixture leaks out through the decompression
valve, as shown in fig. A.
As soon as the engine fires the valve will close due to the combustion
pressure, as in fig. B.
Dismantling
Use a long socket or the
combination spanner to dis-
mantle the decompression valve.
Service
Check that the valve moves.
Carbon removing chemicals or
a light oil (diesel oil) can help a
jammed valve to work again.
Blown clean with compressed
air. Carbon deposits can be
removed using fine emery cloth.
Assembly
Clean the sealing washer and
check that this is not damaged
before assembling the the
decompression valve.
Leakage test
Use a leakage spray or soapy
water. Move the stop button to
the stop position and slowly
pull the starter handle while
observing the decompression
valve.
Dismantling
Use a long socket or the combination
spanner, 506 38 26-01, to dismantle the
decompression valve.
Service
Check that the valve moves. Carbon
removing chemicals or a light oil
(diesel oil) can help a jammed valve to
work again. Blown clean the valve with
com pressed air. Carbon deposits on the
valve and the seating can be removed
using fine emery cloth.
Assembly
Clean the sealing washer and check that
this is not damaged before assembling
the the decompression valve.
Leakage test
The decompression valve can easily be
checked for leakage without starting the
machine. Use a leakage spray or soapy
water. Move the stop button to the stop
position and slowly pull the starter handle
while observing the decompression valve.
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