Disassembling The Carburetor; Checking The Carburetor - Yamaha F4B Service Manual

Disassembling the carburetor

1. Remove the drain screw a.
2. Remove the float chamber b and gasket
c.
a
3. Remove the spring d, and then remove
the pin e.
e
4. Remove the float f, needle valve g,
and clip h.
f
5. Remove the main jet i and main nozzle
j.
c
b
d
g
h
6. Remove the pilot jet k and pilot screw
l.
A For European market
B For Oceanian market
Pilot screw driver m: 90890-06673

Checking the carburetor

1. Check that the throttle valve operates
smoothly.
2. Check the air and fuel passages. Clean
the carburetor body if there is dirt or
foreign material.
3. Blow compressed air into all passages
and jets. WARNING! When
compressed air, wear safety glasses
or safety goggles. Otherwise, eye
injury could result from flying debris
or liquid.
4. Check the main jet, pilot air jet, and main
nozzle. Clean if there is dirt or residue.
NOTICE: Do not use steel wire to
clean the jets. Otherwise, the jet
diameters could be enlarged, which
could seriously affect performance.
Carburetor
i
j
A
m
l
B
l
k
using
6-18
0
1
2
3
4
5
6
7
8
9
10
A