Westerbeke ATOMIC 4 User Manual

IDLE ADJUSTING
NEEDLE
IDlE
MAIN
JET
ADJUST
Fig.65 Carburetor - 63~1 and 263~I
Series
desired idling speed and repeat the
adjustment of idling jet "A".
iVi th the boat under way on smooth
water, open the throttle approxi-
mately 75%. Turn the high speed
jet "B" in until the engine loses
power and RPM. Now open the jet
slowlyuntil the engine runs smoothly
and at its higbest RPM for this
throttle setting.
The carburetor should now be cor-
rectly adjusted for smooth opera-
tion and maximum pouer at all
speeds. A slightly rich fuel mix-
ture is preferable to a lean mix-
ture as a lean mixture has the ap-
parent effect 'of reducing the
octane rating of the fuel and can
result in a tendency toward detona-
tion (ping), burned valves and
scored or 'Worn cyl inders. Therefore,
do not lean out the fuel mixture
in an attempt at fuel economy.
Knight engines with serial number
4979
to 6346 were equipped with a
fixed main jet carburetor intended
to discourage tbe general tendency
to lean out the fuel mixture for
economy but which is actually det-
rimental to the engine. Standard
-52-
Fig.66 Carburetor - 61~ Series
jet size is No. 42 (2.1 mm.) This
jet size should be correct for all
applications., However, if the oper-
ator desires very fine tuning he
may try jets varying from size 41
to 44. but not scalIer than 41.
At the bottom ot" the car'buretor
float bowl will be found a hexagon
head brass plug ';7bere a ve.'.rial>le
main jet is usually found on mar-
ine carburetors. The mein jet is
reached by removing this plug. The
jet itself is a soall, brass threaded
cylinder uith a shoulder e~d a
screwdriver slot at one end. ne~ove
and instC'Jll the jet 't"/ith F:, SC1'e\1-
driver using care Dot to damage
the jet or the threeds in the
carburetor. !Jowl casting. ,The size
number is stamped on the end of
the jet.
This carburet 01' , part number 9005
120, has a t'rlo-hole idle system
that is rf>,ther sensitive in ad-
justment. It 't1ill require more
care in adjusting tbe idle jet
than with the former Knight car-
buretor.
The pC'Jrt number of each carburetor
model will be found stawped on the

Westerbeke ATOMIC 4 Specifications

General

Brand	Westerbeke
Model	ATOMIC 4
Category	Engine
Language	English