MTD P90 series Shop Manual page 44

P90 Series Vertical Shaft Engines
NOTE: Because the float valve is crucial to the func-
tioning of the carburetor and the viton tip of
the valve is subject to wear, technicians
should replace the valve and spring any time
the carburetor is disassembled for cleaning.
NOTE: If the needle seat is worn or damaged, the
carburetor must be replaced.
6. Remove the main jet using a narrow-shank straight
blade screwdriver. See Figure 4.9.
• A square cross-section gasket seals the bowl to
the body of the carburetor.
NOTE: Fuel enters the central column through a
port about 1/2" (1cm) from the bottom to help
prevent the ingress of any residue in the bot-
tom of the bowl.
NOTE: The orifice in the main jet meters fuel into
the central column.
NOTE: Air from the main jet emulsion port enters
the central column near the top, then gets
bubbled through the emulsion tube into the
metered fuel flow to promote atomization.
NOTE: The main jet secures the emulsion tube in the
central column of the carburetor.
See Figure 4.10.
38
Figure 4.8
Main jet
Figure 4.9
Main jet
Emulsion tube
Figure 4.10
Float
Float valve
Compression
spring
Bowl gasket