R e a s s e m b l y
R e a s s e m b l y i s f o r the m o s t p a r t , the r e v e r s e of d i s a s s e m b l y . The following s p e c i a l i n s t r u c t i o n s
should be noted:
M a i n F u e l Valve: P l a c e n e w O - r i n g on i n l e t o r i f i c e a n d t u r n o r i f i c e p a r t w a y i n t o casting.
A f t e r
i n s t a l l i n g f u e l v a l v e l e v e r i n s l o t i n v a l v e s t e m , i n s t a l l a x l e a n d r e t a i n e r .
F o r
p l a c e g a u g e
o n m a c h i n e d s u r f a c e of c a s t i n g a n d a g a i n s t nylon r o l l e r . T u r n i n l e t o r i f i c e in o r out
(with s c r e w d r i v e r
b l a d e ) until f u e l l e v e r i s p o s i t i o n e d i n 3 r d notch (above c a s t i n g f a c e ) o n
gauge. If t h i s g a u g e i s not a v a i l a b l e , s e t a t
a b o v e m a c h i n e d s u r f a c e of c a s t i n g f o r
o r
a t
f o r
m o d e l s . S e c u r e o r i f i c e with 8- 32 A l l e n s e t s c r e w .
D i a p h r a g m A s s e m b l y : I n s t a l l t h r e e aligning s t u d s ( f r o m tool
i n c a s t i n g .
s o o p e n i n g s c o r r e s p o n d - - i n s t a l l in following o r d e r :
1.
G a s k e t .
I n n e r d i a p h r a g m ( s p a c e r cup o u t ) .
3.
D i a p h r a g m s p a c e r ( r e c e s s e d s i d e out).
4.
O u t e r d i a p h r a g m ( d i a p h r a g m p l a t e i n ) .
5.
D i a p h r a g m c o v e r . I n s t a l l t h r e e c o v e r s c r e w s t h e n r e m o v e aligning s t u d s and r e p l a c e
with r e m a i n i n g c o v e r s c r e w s .
Idle D i a p h r a g m : Use new valve d i s c . A f t e r r e i n s t a l l i n g housing a n d l e v e r , p o s i t i o n d i a p h r a g m
s i d e n e x t t o l e v e r ) a n d c o v e r then s e c u r e with c o v e r s c r e w s and l o c k w a s h e r s .
A f t e r c a r b u r e t o r i s c o m p l e t e l y r e a s s e m b l e d , m a k e p r e l i m i n a r y a d j u s t m e n t s a s shown in F i g u r e
C a r e f u l l y c h e c k c a r b u r e t o r and c o n n e c t i o n s f o r l e a k s a f t e r r e i n s t a l l i n g on engine.
GAS REGULATORS
Model
( F )
a n d KN s e c o n d a r y r e g u l a t o r s a r e u s e d . While t h e y d i f f e r in a p p e a r a n c e , they a r e
s i n g l e d i a p h r a g m t y p e r e g u l a t o r s which f u n c t i o n to c o n t r o l the a m o u n t of f u e l e n t e r i n g a n engine u n d e r
v a r y i n g s p e e d a n d l o a d c o n d i t i o n s . Vacuum c r e a t e d within the engine i s c o m m u n i c a t e d t o one s i d e of
the d i a p h r a g m while the o t h e r s i d e i s s u b j e c t t o a t m o s p h e r i c p r e s s u r e . M o v e m e n t of the d i a p h r a g m
c a u s e d by t h i s d i f f e r e n c e i n p r e s s u r e i s t r a n s m i t t e d t h r o u g h linkage t o the f u e l valve which opens t o
a d m i t f u e l t o t h e c a r b u r e t o r . T h e h i g h e r the p r e s s u r e d i f f e r e n t i a l , the g r e a t e r the volume of fuel.
The s e c o n d a r y r e g u l a t o r r e c e i v e s f u e l f r o m the p r i m a r y r e g u l a t o r a t a p r e s s u r e of 4 t o
7
o u n c e s
p e r s q u a r e inch
w a t e r c o l u m n ) a n d r e d u c e s t h i s t o a b o u t 3 o u n c e s when the engine i s a t idle.
When the engine i s s t o p p e d , the f u e l valve i n the s e c o n d a r y r e g u l a t o r should c l o s e t o p r e v e n t f u e l f r o m
e n t e r i n g the c a r b u r e t o r . A m a n u a l o r e l e c t r i c a l l y o p e r a t e d f u e l shut- off valve i s often u s e d in the
s y s t e m t o p r o v i d e a m o r e p o s i t i v e m e a n s of t u r n i n g off the f u e l .
TROUBLE ANALYSIS
CONDITION
ENGINE FAILS T O S T A R T
ENGINE IDLES P O O R L Y
ENGINE O P E R A T E S P O O R L Y UNDER LOAD
POSSIBLE F A U L T
1.
Main d i a p h r a g m b r o k e n o r linkage
n o f u e l .
2.
F u e l valve s t u c k o p e n - - t o o m u c h fuel.
1.
Idle l i n e c o n n e c t i o n s l e a k i n g o r plugged.
2 .
D i a p h r a g m stiff o r r u p t u r e d .
3 .
B a l a n c e l i n e plugged.
1.
E x c e s s i v e p r e s s u r e - - r e g u l a t o r d i s c h a r g e s
in s u r g e s .
2.
B a l a n c e l i n e i m p r o p e r s i z e o r r e s t r i c t e d .
3.
D i r t i n r e g u l a t o r c a u s i n g s t i c k i n g o r s l u g g i s h
o p e r a t i o n of f u e l valve.
