Kärcher KMR 1250 B Service Manual page 11

KMR 1250 B, LPG, D
LP Gas Engine (HONDA GX 270)
Gas system
– Opening the shutoff valve (3) on the LP gas
cylinder (5) causes gas to flow through the gas
filter (13). At this point, possible contaminants
are trapped in a paper filter, and metallic par-
ticles from gas cylinder are removed by means
of a small magnet.
– Setting ignition key to Pos. 1 (ON) opens so-
lenoid valve (14), allowing LP gas to flow from
gas filter (13) into primary chamber of gas reg-
ulator (16). Here, a spring-loaded valve reduc-
es gas pressure to approximately 150 mbar
(2.2 psi).
– When starter begins to crank engine (10), a
vacuum is created in the suction channel.
Through vacuum line (11), this vacuum acts
on low-pressure diaphragm in secondary stage
of gas regulator. Diaphragm opens low-pres-
sure valve, and gas can be drawn into engine.
– Pressing choke button causes choke lifting
solenoid (17) to open low-pressure valve, al-
lowing gas to flow directly through carburetor
and into engine. This function is particularly
important in cold-starting situations. To pre-
vent high-level enrichment of intake mixture
with LP gas, choke button should not be
pressed for longer than 3-5 seconds.
Note:
The connection on cylinder shutoff valve (3)
must face straight up (extraction of LP gas
in gaseous state).
Carburetor in LP gas operation (example)
– The presence of frost on any part of the LP gas
system indicates a possible leak. Close the
cylinder shutoff valve (3) immediately. Apply
suitable leak detection medium (soapy water
or Leak Detecting Spray 6.282-033) to gas
lines, solenoid valve, gas regulator and gas
hose to carburetor. Open cylinder shutoff valve
(3), and check for formation of bubbles. The
unit may be returned to service only after thor-
ough repairs have been carried out by ap-
proved specialists.
Note:
The LP gas system of the unit must be in-
spected by a licensed expert in 6-month
intervals. The results of each inspection must
be made available in the form of a test cer-
tificate.
– An expert is deemed to be a person who, based
on his professional education and skills, pos-
sesses sufficient knowledge of, and expertise
in, the field of LP gas systems, and who is
sufficiently familiar with applicable working
directives and accident prevention regulations,
as well as commonly accepted procedures of
this technology, all of the above enabling him
to evaluate, determine and assess the safe
operational state of LP gas systems.
Note:
For information on other maintanance and
adjustments of the engine, refer to the Serv-
ice manual "4-Stroke Internal Combustion
Engines" (5.905-122).
Gas regulator
– Engines using LP gas as a fuel are equipped
with a gas regulator which feeds LP gas to the
carburetor of a gasoline engine. The carbure-
tor generates an air/fuel mixture which is drawn
into the combustion chamber for ignition.
1 Gas inlet
2 Air intake
3 Air/fuel mixture outlet
4 Mixing chamber
5 Gas jet
Unit Functions
11