AUTOMATIC CHOKES
Two d i f f e r e n t e l e c t r i c
t h e r m o s t a t i c type a u t o m a t i c c h o k e s a r e u s e d on the
m o d e l s . One
type i s a n i n t e g r a l p a r t of a s p e c i a l down d r a f t c a r b u r e t o r while the o t h e r type i s mounted o n the
e x h a u s t manifold and connected through e x t e r n a l linkage t o the choke p l a t e in c a r h u r e t o r .
Both types o p e r a t e on the s a m e b a s i c p r i n c i p l e s .
The e l e c t r i c a l l e a d t o the choke i s connected
s o t h a t c u r r e n t flows t o the t h e r m o s t a t i c e l e m e n t only when the ignition i s t u r n e d on.
Tension of the
t h e r m o s t a t i c
i s s e t to allow full choke a t s t a r t i n g . C u r r e n t t h r o u g h a heating e l e m e n t f u r n i s h e s
h e a t t o c o n t r o l t e n s i o n of the
s p r i n g which c a u s e s the choke plate to be g r a d u a l l y r e t u r n e d
t o the open p o s i t i o n a s the engine w a r m s up.
The a u t o m a t i c c h o k e s a r e a d j u s t e d i n the f a c t o r y , h o w e v e r , s l i g h t r e a d j u s t m e n t m a y be
s a r y initially t o a c c o m m o d a t e d i f f e r e n t s t a r t i n g conditions. A d j u s t c h o k e s a s follows:
C a r b u r e t o r Unit: Choke unit i s s e t f o r a v e r a g e conditions. T o r e a d j u s t t o l o c a l s t a r t i n g conditions,
l o o s e n s c r e w s on o u t s i d e of c o v e r p l a t e t h e n s h i f t c o v e r in c l o c k w i s e d i r e c t i o n ( a r r o w ) f o r r i c h e r s e t -
ting o r in c o u n t e r c l o c k w i s e d i r e c t i o n f o r l e a n e r s e t t i n g . Tighten c o v e r s c r e w s a f t e r f i n a l a d j u s t m e n t .
E x h a u s t Manifold Mounted Unit: R e m o v e a i r c l e a n e r f r o m c a r b u r e t o r t o o b s e r v e position of choke
p l a t e . Choke a d j u s t m e n t m u s t b e m a d e o n cold engine. If s t a r t i n g in e x t r e m e cold, choke should be in
full c l o s e d p o s i t i o n
engine i s s t a r t e d .
A
l e s s e r d e g r e e of choking i s needed i n m i l d e r t e m p e r a -
t u r e s . If a d j u s t m e n t i s n e e d e d , p r o c e e d a s follows:
1 .
Move choke a r m until hole in b r a s s s h a f t l i n e s up with s l o t in b e a r i n g s .
2 .
I n s e r t # 4 3 d r i l l
089) a n d p u s h a l l the way dawn t o engine manifold t o engage in notch in
of choke unit
( S e e
F i g u r e
3 .
L o o s e n c l a m p bolt on choke l e v e r , p u s h a r m u p w a r d t o move choke p l a t e toward c l o s e d
position. A f t e r d e s i r e d p o s i t i o n i s a t t a i n e d , t i g h t e n c l a m p
then r e m o v e d r i l l .
4.
A f t e r r e p l a c i n g a i r c l e a n e r , c h e c k f o r evidence of binding in l i n k a g e - - c o r r e c t if n e c e s s a r y .
Be s u r e c h o k e s a r e fully open when engine i s a t n o r m a l o p e r a t i n g t e m p e r a t u r e .
TERMINAL
CHOKE LEVER ARM
.
I
N
BASE
A
I
I
I
B
FIGURE
4-9
AUTOMATIC CHOKES ( A ) CARBURETOR U N I T
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MANIFOLD UNIT