IGNITION
SYSTEMS
While the s o u r c e of e n e r g y f o r the ignition s y s t e m m a y be e i t h e r m a g n e t c o r b a t t e r y ( g e n e r a t o r
o r a l t e r n a t o r ) , m o s t o t h e r c o m p o n e n t s a r e c o m m o n in function i n a l l s y s t e m s e v e n though they m a y not
b e a l i k e in a p p e a r a n c e o r l o c a t i o n .
When c h e c k i n g o u t a n ignition s y s t e m , s t a r t with the c o m p o n e n t s t h a t r e q u i r e m o s t f r e q u e n t s e r -
v i c e o r a d j u s t m e n t .
H a r d s t a r t i n g , r o u g h n e s s , low p o w e r and e r r a t i c o p e r a t i o n a r e o f t e n a t t r i b u t e d t o
faulty ignition. A l l c o m p o n e n t s m u s t be in top condition and the ignition s p a r k m u s t b e p r o p e r l y t i m e d
t o m a i n t a i n good p e r f o r m a n c e .
SPARK PLUG
E n g i n e m i s f i r e o r g e n e r a l l y p o o r o p e r a t i o n i s o f t e n c a u s e d b y s p a r k plugs i n poor condition o r
with i m p r o p e r g a p s e t t i n g . Always c l e a n a r e a a r o u n d s p a r k p l u g s b e f o r e r e m o v i n g t o p r e v e n t d i r t
f r o m f a l l i n g i n t o e n g i n e . T h e f i r s t thing t o d o a f t e r r e m o v i n g a s p a r k plug i s t o c a r e f u l l y note i t s con-
d i t i o n a s t h i s i s o f t e n a n i n d i c a t o r of t h e ignition t r o u b l e . P l u g s f a i l f o r v a r i o u s r e a s o n s . Often the
p o r c e l a i n i n s u l a t o r c r a c k s o r b e c o m e s c o a t e d with o i l , c a r b o n o r o t h e r d e p o s i t s .
T h i s c a n c a u s e the
high voltage ignition i m p u l s e t o p a s s f r o m the c e n t e r e l e c t r o d e t o g r o u n d without jumping the s p a r k gap.
A s a n engine o p e r a t e s , the e l e c t r o d e s a r e g r a d u a l l y b u r n e d o r w o r n away. In t i m e ,
gap b e c o m e s
s o wide t h a t the a v a i l a b l e ignition voltage c a n n o t jump the gap a n d the engine m i s s e s .
S p a r k P l u g S e r v i c e : E v e r y 100 h o u r s r e m o v e p l u g , c h e c k condition a n d r e s e t gap. Good o p e r a t i n g con-
d i t i o n s a r e i n d i c a t e d if plug h a s l i g h t coating of g r a y o r t a n d e p o s i t . A d e a d white, b l i s t e r e d coating
could i n d i c a t e o v e r h e a t i n g .
A
b l a c k ( c a r b o n ) coating m a y i n d i c a t e a n
f u e l m i x t u r e c a u s e d
b y clogged a i r c l e a n e r o r i m p r o p e r c a r b u r e t o r a d j u s t m e n t . Do not s a n d b l a s t , w i r e b r u s h , s c r a p e o r
o t h e r w i s e s e r v i c e plug i n p o o r c o n d i t i o n - - b e s t r e s u l t s a r e
with new plug.
SPARK PLUG DETAILS
MODEL
I G N I T I O N TYPE
PART NO.
GAP
i n .
B a t t e r y
"Standard resistor plug.
BREAKER POINTS
E n g i n e o p e r a t i o n i s g r e a t l y a f f e c t e d b y b r e a k e r point c o n d i t i o n a n d a d j u s t m e n t of the gap.
If
p o i n t s a r e b u r n e d o r b a d l y o x i d i z e d , l i t t l e o r no c u r r e n t will p a s s a n d a s a r e s u l t the engine m a y not
o p e r a t e a t a l l , o r if i t d o e s r u n i t i s l i k e l y t o m i s s p a r t i c u l a r l y a t f u l l t h r o t t l e . Adjusting b r e a k e r
point gap a f f e c t s the t i m e t h a t the c o n t a c t s a r e opened and c l o s e d .
If
the points a r e a d j u s t e d t o a w i d e r
gap, t h e y will open e a r l i e r and c l o s e l a t e r i n t e r m s of c a m m o v e m e n t . A d e f i n i t e t i m e i s r e q u i r e d f o r
t h e m a g n e t i c f i e l d within the ignition c o i l t o build up t o s u f f i c i e n t v a l u e . If the c o n t a c t points a r e
c l o s e d f o r too s h o r t a t i m e , a weak s p a r k w i l l b e p r o d u c e d by t h e coil. If points a r e s e t too wide, t h e y
w i l l open b e f o r e the p r i m a r y c u r r e n t r e a c h e s the m a x i m u m value and o n the o t h e r hand if s e t too c l o s e ,
t h e y will open a f t e r the p r i m a r y c u r r e n t h a s p a s s e d i t s m a x i m u m v a l u e .
I
Always r e p l a c e b a d l y b u r n e d o r p i t t e d b r e a k e r p o i n t s . A c e r t a i n a m o u n t of build up o r m e t a l
t r a n s f e r o c c u r s u n d e r n o r m a l o p e r a t i n g c o n d i t i o n s ; h o w e v e r , if t h i s o c c u r s too f r e q u e n t l y and b e c o m e s
e x c e s s i v e , the c o n d e n s e r m a y be a t f a u l t - - s e e C o n d e n s e r S e r v i c e f o r d e t a i l s . Slightly p i t t e d points
c a n h e d r e s s e d down with a point f i l e , a l t h o u g h t h i s should be done only a s a t e m p o r a r y f i e l d f i x s i n c e
p o i n t s m a y tend t o a r c m o r e r e a d i l y a f t e r filing. R e p l a c e points a t f i r s t opportunity a f t e r filing. If the
p o i n t s a r e oxidized, r u b a p i e c e of c o a r s e c l o t h b e t w e e n the s u r f a c e s . D i r t y o r oily
b e
c l e a n e d with c l o t h b u t m a k e s u r e no p a r t i c l e s of l i n t a r e l e f t b e t w e e n s u r f a c e s . On e n g i n e s equipped with
t h e A l t e r n a t o r
the b r e a k e r p o i n t s a r e e x t e r n a l l y mounted o n the g o v e r n o r and o p e r a t e d off a
c a m o n the g o v e r n o r d r i v e s h a f t . O n e n g i n e s with the e x t e r n a l u n i t m a g n e t o s , the b r e a k e r points a r e
l o c a t e d i n s i d e the m a g n e t o . R e f e r t o Magneto o r A l t e r n a t o r h e a d i n g s (depending on type u s e d on the
e n g i n e ) i n t h i s s e c t i o n f o r s p e c i f i c d e t a i l s o n b r e a k e r points o r c o n t a c t s .
Magneto
i n .
*41 1 3 2 0 6
i n .
