David Brown Cropmaster VAK1 Series, Operating And Maintenance Instructions Manual, Page: 31 / 51

MINOR SERVICE AND ADJUSTMENTS
Valve clearances are determined with the engine hot ; they should he
roughly set and the engine warmed up to normal working temperature
before the final adjustment is made.
Adjust No. 1 valve with No. 8 valve fully open.
,, No. 6 ,, ,, No. 3 ,, ,, ,,
,,
No. 4 ,, ,, No. 5 ,, ,, ,,
,, No. 2 ,, ,, No. 7 ,, ,, ,,
,, No. 8 ,, ,, No. 1 ,, ,, ,,
,, No. 3 ,, ,, No. 6 ,, ,, ,,
,, No. 5 ,, ,, No. 4 ,, ,, ,,
,, No. 7 ,, ,, No. 2 ,, ,, ,,
After the final setting has been made, warm up the engine again to
normal working temperature, check the tightness of the cylinder head bolts
and nuts and re-check the valve clearances.
NOTE: Cylinder head bolts should be tightened in sequence (see
Fig. 19).
FIJEL �YSTEM
Ca,·burettor
A strainer incorporated in the fuel inlet of the carburettor is removed
for cleaning by unscrewing the banjo nut shown in Fig. 17. To clean, use
a stiff. brush and fire with petrol. When the strainer is cool, the �ust
remaining on it can be blown away-do not attempt to wipe it clean with
a rag.
To clean the float chamber and obtain access to the jets (the latter
only if partial blocking is suspected), remove the lower half of the
carburettor by disconnecting the choke control, releasing the clips on the
air. intake hose and sliding the hose toward the air cleaner. Unscrew the
two square-headed bolts above the float chamber and two hexagon bolts
which are in line with the throttle spindle, also release the balance pipe
from the air intake elbow. The lower half can then be drawn downwards.
The slow-running jet is
located at .the side of the
main jet and is immed­
iately visible, but the
carrier tube cap must he
taken. off to obtain access
to the main jet. (See
vertical type carburettor,
30 F.V., Fig. 17.) When
cleaning, do not use a rag
but a stiff brush and
vaporizing · oil. Free the
float chamber from sludge,
unscrew the main jet
carrier tuhe and float
needle assembly and
clean the jets and ducts
i,y air blast.
PAGE 30
THROTTLE
LEVER
THROTTLE
BUTTERFLY
SMALL FIBRE
WASHER
NEEDLE SEATING
NEEDLE
BA°itJO UHIOM
LARGE FIBRE
WASHER
STRANGLER MAIN JET COMPENSATING FLOAT BANJO
JET CAP CHAMBER CONNECTION
F'IG. 17
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