Zundapp 281 - Page 44

Starter Systems
To start a cold engine needs a specially enriched fuel mixture. To supply this, many
carburettors have a separate starting system.
Starter
Air
Shutter
(see
carburettor
for
R
50
and
RS
50)
On some carburettor types, the starting aid consists of a pivoted shutter in the filter
chamber, operated by Bowden cable. When the starter knob is pulled, the shutter
substantially
narrows
the
carburettor
cross
section,
so
that
the
mixture
will
become
rich enough to start a cold engine.
Starter Air Slide (see carburettors for KS 50 Super, Sport-Combinette and Super-Com-
binette 433)
With
these
designs,
the
engine
is
started
from
cold
as
follows:
Close
throttle
slide
all
the
way,
and
with
the
pressure
pin
and
knob,
press
the
starter
slide
down.
As
you
start,
pull
out
throttle
about
one-third
to
one-half
of
the
way
to
a
clearly
perceptible
stop.
Once
the
engine
has
come
to
life,
leave
the
throttle
in
this intermediate
position,
until
the
engine
has run
itself
warm.
Then
open
throttle
all
the
way,
and
this
will also
raise
the
starter
slide
to
its
end
position
where
it
engages.
If
on
starting
you
inadver-
tently
pull
out
the
throttle
too
far
so
that
it
overrides
the
stop
and
takes
the
starter
slide
with
it,
so
that
the
knob
jumps
back
again,
press
the
starter
knob
once
more.
Starter-Jet
Carburettors
(see
carburettor
for
KS
100)
On these designs, a cylindrical starter-jet housing is arranged next to the main hous-
ing, whose piston is operated by Bowden cable. In its top position, the piston un-
covers the port which admits starting air from the filter socket and the starting fuel
mixture port leading to the carburettor intake socket. Fuel enters from below through
the
starter
jet
into
this
housing,
which
generally
also
has
a
storage
chamber.
When the engine is started from cold, the piston is raised, while the throttle slide
remains closed. The fuel is first drawn from the storage chamber and when this is
empty, through the starter jet. It is then mixed with the starting intake air to produce
at first a very rich mixture which becomes gradually leaner as it flows directly into
the intake socket of the carburettor and from there to the engine. Once the engine has
run itself warm, shut off the starter piston.
44