Stihl 140, Repair Manual, Page: 11 / 31

- Connect test pressure gauge
5910 850 3205 between high-
pressure port and high-pressure
hose.
- Connect water inlet and high-
pressure hose.
•
Completely unscrew the micro-
switch adjusting screw (1) with a
size 2.5 hexagon socket wrench.
- Switch on machine.
- Open spray gun.
- Set maximum working pressure
on spray lance.
•
Back off adjusting nut (2)
until pressure has dropped
completely.
•
Screw adjusting nut in again until
reading on pressure gauge no
longer increases (maximum
working pressure).
- The setting is adjusted precisely
by slowly backing off and scre-
wing in the adjusting nut.
The bypass valve is set correctly
when the adjusting nut is screwed
in precisely to the point necessary
for the maximum pressure
(reading on pressure gauge) to be
barely reached.
- Let machine run for approx.
10 seconds. Operate the spray
gun two or three times.
Note: The maximum pressure
and cutout pressure settings are
determined by the adjusting nut.
Ensure that the cutout pressure
does not become too high by scre-
wing the nut in further.
The cutout pressure (= pressure
at which the bypass valve opens)
must be 5 bar higher than the
maximum working pressure
(see 3.2).
To check the setting:
- Close spray gun and read off
cutout pressure value on
pressure gauge.
If the value is too high:
- Open spray gun.
- Back off adjusting nut slightly.
- Close spray gun.
- Check cutout pressure.
Repeat this procedure until the
specified cutout pressure (see
above) has been reached. The
working pressure must not
decrease at the same time
(reading on pressure gauge when
spray gun is open).
The cutout pressure must also
remain constant. If necessary, the
setting must be repeated or the
high-pressure cleaner examined
for leaks.
The microswitch is set with the aid
of the adjusting screw when the
motor is running and with the
spray gun closed:
- Turn adjusting screw in until
motor cuts out.
- Then turn on another half-turn.
- Check setting at minimum
pressure and correct if necessa-
ry.
- Actuate spray gun several times.
The motor must switch on when
the spray gun is opened and
off when it closes; repeat
adjustment if necessary.
- Seal setting of locknut and
adjusting screw with locking
paint.
- Remove test pressure gauge.
6.3 Set pressure
control system
621RA076 BL
1
2
RE 140 K, 160 K 11