KOHLER #A- 271923 ( M O D E L
GAS CARBURETOR
T h e m o d e l
c a n be c l a s s i f i e d a d i a p h r a g m type c a r b u r e t o r a l t h o u g h i t a l s o u s e s a v e n t u r i .
The d i a p h r a g m a r r a n g e m e n t p r o v i d e s f i n a l r e g u l a t i o n of the f u e l which i s r e c e i v e d f r o m the p r i m a r y
r e g u l a t o r ( o r v a p o r i z e r - r e g u l a t o r ) a t a p r e s s u r e of a b o u t
8
p s i . T h i s p r e s s u r e s e t t i n g m u s t not e x c e e d
12
p s i . The P C 2 s e r v e s two f u n c t i o n s - - a s a c a r b u r e t o r a n d a s the s e c o n d a r y r e g u l a t o r .
O p e r a t i o n : F u e l i s s u p p l i e d t o the c a r b u r e t o r a t above a t m o s p h e r i c p r e s s u r e - - a s long a s inlet p r e s -
s u r e d o e s not e x c e e d 20 p s i , the r e g u l a t o r s e g m e n t will b l o c k off f u e l a n d p r e v e n t l e a k a g e i n t o the
engine when i t i s not o p e r a t i n g . B r i e f l y , when the engine i s i n o p e r a t i o n , flow of a i r t h r u the c a r b u r e -
t o r c a u s e s p r e s s u r e d i f f e r e n c e s which a c t upon d i a p h r a g m s w h i c h , i n t u r n , a c t i v a t e a f u e l l e v e r t o
a d m i t f u e l a c c o r d i n g t o engine d e m a n d . When the engine i s a t low i d l e s p e e d s , t h e f u e l i s d i r e c t e d
i n t o the engine t h r u s e p a r a t e idle d i s c h a r g e j e t s which p e r m i t o p e r a t i o n e v e n when flow of a i r t h r o u g h
the v e n t u r i would b e too low t o d r a w s u f f i c i e n t f u e l t o s u s t a i n o p e r a t i o n . T h e c a r b u r e t o r a l s o f e a t u r e s
a b a c k s u c t i o n type of " e c o n o m i z e r " which m e t e r s a n e c o n o m y m i x t u r e of f u e l d u r i n g p a r t t h r o t t l e and
p a r t load o p e r a t i o n . A t f u l l t h r o t t l e and full l o a d o p e r a t i o n , the p o s i t i o n of the t h r o t t l e p l a t e i s s u c h
t h a t m a x i m u m f u e l i s m e t e r e d t o the engine.
The m a x i m u m a m o u n t
f u e l a l l o w e d i s d e t e r m i n e d by
s e t t i n g of the m a i n f u e l ( l o a d ) a d j u s t m e n t .
A d j u s t m e n t : F o r p r e l i m i n a r y a d j u s t m e n t of c a r b u r e t o r r e f e r t o F i g u r e
T u r n s c r e w s in l i g h t l y
a g a i n s t s e a t s - - b e f o r e opening- - do not f o r c e c l o s e d . F i n a l a d j u s t m e n t s a r e m a d e a s follows:
Idle: S t a r t e n g i n e , move t h r o t t l e t o idle p o s i t i o n , a d j u s t idle s p e e d t o p r o p e r r a n g e . Move idle
a d j u s t i n g s c r e w in and out u n t i l s m o o t h e s t idle i s a t t a i n e d .
Load: Allow engine t o w a r m up, then open t h r o t t l e a n d p l a c e u n d e r n o r m a l load.
m a i n
i n until engine s t a r t s t o slow down f r o m l e a n m i x t u r e t h e n t u r n a d j u s t m e n t i n the
opposite d i r e c t i o n until engine s p e e d i n c r e a s e s then s t a r t s t o s l o w down a g a i n f r o m
m i x t u r e . Move a d j u s t m e n t halfway b e t w e e n l e a n a n d
s e t t i n g s f o r b e s t m i x t u r e u n d e r
n o r m a l l o a d .
Reconditioning: The P C 2 d o e s not r e q u i r e s e r v i c e a t r e g u l a r i n t e r v a l s . If c a r b u r e t o r t r o u b l e s o c c u r
t h a t c a n n o t b e r e m e d i e d by r e a d j u s t m e n t , the c a r b u r e t o r should be c o m p l e t e l y d i s a s s e m b l e d and r e c o n -
ditioned. R e p l a c e a l l d i a p h r a g m s , g a s k e t s , O - r i n g s and d u s t s e a l s when r e c o n d i t i o n i n g . Use the
R e p a i r Kit
( s e e
p a r t s m a n u a l ) f o r t h i s c a r b u r e t o r when reconditioning.
The following s p e c i a l
t o o l s a r e r e q u i r e d f o r s a t i s f a c t o r y o v e r h a u l : Main J e t W r e n c h
F u e l Valve L e v e r Gauge
Aligning Studs
s e t ) .
LEVER
FIGURE 12-6
GAS CARBURETOR
