Disassembling The Carburetor; Checking The Carburetor; Checking The Float Height - Yamaha 55DEHD Service Manual

FUEL

Disassembling the carburetor

NOTE:
Disassembled jets and other components
should be sorted out and kept in order, so
that they can be re-assembled in their original
positions.

Checking the carburetor

1. Check the air and fuel passages and jets.
Clean the carburetor body with a petrole-
um based solvent if dirt and foreign mat-
ter.
2. Blow compressed air into all passages
and jets.
w
Wear appropriate protective eye gear dur-
ing the cleaning process to prevent any
eye injury by the blown-off debris or liq-
uid.
3. Check the main jet, pilot jet and main
nozzle. Clean if dirt or residue appears.
cC
Do not use steel wire for cleaning the jets,
otherwise the jet diameters may be
enlarged, which may seriously affect per-
formance.
4-13
Fuel system
69R40090
4. Check the pilot screw and needle valve.
Replace the pilot screw and needle valve
if bend or worn.
5. Check the float. Replace the float if
cracked or damaged.

Checking the float height

1. Measure the float height. Replace the
float and needle valve as a set, if out of
specification.
NOTE:
When measure the float height, the float
should not be compressing.
Digital caliper 1: 90890-06704
Float height a:
16.5–22.5 mm (0.65–0.89 in)
6B440040
1
a
68840040
6885J11