Carburetor Adjustments - Briggs & Stratton 190700 Operating And Maintenance Instructions Manual

S e c t i o n
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M A I N T E N A N C E (cont'd)
(T)CLEAN
COOLING SYSTEM - Grass, chaff or d i r t may
clog the air c o o l i n g s y s t e m , e s p e c i a l l y after prolonged
service c u t t i n g dry g r a s s e s . To avoid overheating and
engine damage, remove the blower housing and c l e a n
the area shown. This should be a regular maintenance
operation.
(T^CLEAN FUEL SYSTEM - Drain and c l e a n fuel t a n k .
(T)CLEAN
SPARK PLUG - Clean and reset gap at . 0 3 0 "
every 100 hours of operation.
CAUTION: Blast c l e a n i n g of spark plugs in machines
that use a b r a s i v e g r i t is not recommended. Spark plugs
should be cleaned by scraping or w i r e brushing and
washing w i t h a commercial s o l v e n t or g a s o l i n e .
WITHIN HEAVY
LINE C L E A R
OF A L L
CEBRIS
Clean C o o l i n g System
S e c t i o n
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ADJUSTMENTS
CARBURETOR ADJUSTMENTS
Minor carburetor adjustment may be required t o com-
pensate for differences in f u e l , temperature, a l t i t u d e
and load.
To A d j u s t Carburetor Turn needle v a l v e c l o c k w i s e
until it j u s t c l o s e s . C a u t i o n : V a l v e may be damaged
by turning it in too far.
Now open needle v a l v e 1-1/8 turns c o u n t e r c l o c k w i s e .
Close idle v a l v e in same manner and open 1-1/8 t u r n s .
This i n i t i a l adjustment w i l l permit t h e engine t o be
started and warmed up prior t o f i n a l adjustment.
IDLE SPEED
ADJUSTING SCREW
NEEDLE VALVE
Final Adjustment Turn needle v a l v e in until engine m i s s e s (lean m i x t u r e ) . Then turn it out past smooth operat-
ing point until engine runs unevenly ( r i c h mixture). Now t u r n needle v a l v e t o the mid-point between rich and lean
so the engine runs smoothly. H o l d t h r o t t l e at idle p o s i t i o n and s e t idle speed a d j u s t i n g screw u n t i l f a s t idle is
obtained (1750 RPM). H o l d t h r o t t l e in idle p o s i t i o n and turn idle v a l v e in (lean) and out (rich) u n t i l engine idles
smoothly. Then reset idle speed a d j u s t i n g screw so t h a t engine i d l e s at 1750 RPM. Release t h r o t t l e - engine
should accelerate w i t h o u t h e s i t a t i o n or s p u t t e r i n g . If engine does not a c c e l e r a t e p r o p e r l y , t h e carburetor should
be re-adjusted t o a s l i g h t l y richer mixture.
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