Check that the tank venting valve works
531 03 06-23
Fuel ﬁ lter
The fuel ﬁ lter can be removed through the
tank's ﬁ ll hole.
502 50 83-01
Clean the ﬁ lter externally if it is not too
Replace the ﬁ lter if required.
Tank venting takes place through the fuel
cap and needs to be functional for the
engine to work.
Remove the starter.
Remove the air ﬁ lter cover and
dismantle the cylinder cover.
Remove the fuel hose from the
carburettor, remove the fuel tank and
empty the tank of fuel.
Connect the fuel hose to pressure
tester part number 531 03 06-23 and
plug the return line shut.
Make sure that the hose bushings in
the tank are leak tight.
Pump up a pressure and vacuum of 50
kPa (0.5 bar) in the tank.
The pressure should drop to 20 kPa
(0.2 bar) or revert to atmospheric
pressure within 45 seconds.
The fuel cap can be taken apart for clea-
Use a screwdriver and press off the hou-
sing (A) that contains a rubber diaphragm
(B) and a ﬁ lter (C) and cover (D).
Blow the ﬁ lter (C) clean, and the sintered
ﬁ lter (E), with compressed air and mount
the fuel cap in the reverse order to how it
Make sure that the ﬂ at surface on the co-
ver (D) is turned towards the diaphragm.
There is a small slit (F) in the
diaphragm (B) that becomes visible
when you carefully pull the edges
of the diaphragm. Check that the
edges of the slit are not damaged.
Replace diaphragm if necessary.
Fuel ﬁ lter
The fuel hose in the tank contains a fuel
ﬁ lter. It is accessible through the ﬁ ll hole.
Pull out the ﬁ lter with your ﬁ ngers or with
help of tool 502 50 83-01.
If the ﬁ lter is not too dirty, its surface can
be cleaned with a brush.
Otherwise it must be replaced.
Check the fuel hose for cracks and leaks.
Make sure that the ﬁ lter's connection neck
is inserted as far as possible into the fuel
hose and that the O-ring is sufﬁ ciently
tight so that the ﬁ lter cannot slide off the