Synchronizing The Carburetor - Yamaha F40BMHD Manuel D'entretien

CHK
CONTROL SYSTEM
ADJ
1
3
1
2

SYNCHRONIZING THE CARBURETOR

CAUTION:
Do not adjust the carburetor when it is
operating properly. Excess adjustment may
cause the engine poor performance.
1. Check:
• Engine idling speed
Unstable → Adjust.
2. Adjust:
• Carburetor synchronization
Adjustment steps
(1) Remove all of the plugs
(2) Install the adaptors
3
gauge onto the intake manifold as
shown.
Vacuum gauge set
YU-08030/90890-03159
(3) Start the engine and allow it to warm
up for several minutes.
(4) Install the tachometer onto the spark
plug lead of cylinder #1.
Tachometer
YU-08036-A/90890-06760
(5) Adjust the engine speed to 900 r/min by
turning the throttle stop screw
carburetor #3 in direction
D D D D i i i i r r r r e e e e c c c c t t t t i i i i o o o o n n n n a
D D D D i i i i r r r r e e e e c c c c t t t t i i i i o o o o n n n n b
(6) Measure the vacuum pressure of carbu-
retor #3.
3-9
1
.
2
and vacuum
a
or
Engine speed increases.
Engine speed decreases.
E
4
on
b
.