AIR-VAC COOLING
With optional a i r - v a c c o o l i n g , a i r c i r c u l a t i o n i s opposite t o t h a t of the s t a n d a r d s y s t e m . On
equipped e n g i n e s , a b l o w e r unit and s u p p o r t a r e a t t a c h e d t o a s p e c i a l flywheel which d o e s not have
f i n s . R o t a t i o n of the b l o w e r c a u s e s cooling a i r t o be d r a w n in f r o m the s i d e s and r e a r of the e n g i n e ,
p a s t the cooling f i n s and i n t o the s p e c i a l s c r o l l w o r k l o c a t e d a t f r o n t of engine. F r o m h e r e , the h e a t e d
a i r is e j e c t e d u s u a l l y t o w a r d e i t h e r s i d e of the e n g i n e - - t h e s c r o l l c a n a l s o b e mounted t o o u t l e t i n up o r
down p o s i t i o n s depending o n the a p p l i c a t i o n . The
s e r v i c e r e q u i r e d with t h i s s y s t e m i s t o m a k e
s u r e t h a t cooling f i n s , b l o w e r a n d o u t l e t s c r e e n a r e m a i n t a i n e d i n c l e a n condition a t a l l t i m e s t o p r e -
vent o v e r h e a t i n g due t o r e s t r i c t e d a i r c i r c u l a t i o n .
S p e c i a l cold w e a t h e r e q u i p m e n t is a l s o a v a i l a b l e with A i r - V a c s y s t e m s . T h i s s y s t e m i s c o m -
p r i s e d of a t h e r m o s t a t i c a l l y o p e r a t e d a i r s h u t t e r unit a n d o f t e n i n c l u d e s a c a r b u r e t o r d e - i c e r o r h e a t -
ing unit. When the engine i s c o l d , the s h u t t e r s a r e held i n p a r t i a l l y c l o s e d p o s i t i o n t o r e s t r i c t a i r
c i r c u l a t i o n t h e r e b y allowing m o r e r a p i d w a r m up of the engine.
A
b e l l o w s type t h e r m o s t a t , which i s
mounted on a b r a c k e t on the c y l i n d e r h e a d , g r a d u a l l y e x p a n d s with i n c r e a s i n g t e m p e r a t u r e . This
a c t i o n i s t r a n s m i t t e d t h r o u g h b a l l joint linkage t o g r a d u a l l y o p e n the s h u t t e r s with i n c r e a s i n g o p e r a t i n g
t e m p e r a t u r e s . When engine i s thoroughly w a r m e d u p , the s h u t t e r s will he wide o p e n ( u n l e s s o p e r a t i n g
in s e v e r e c o l d ) , a n d o f f e r z e r o r e s t r i c t i o n t o a i r flow.