Polaris Trail Boss 330 2003 Service Manual page 101

FUEL SYSTEM/CARBURETION
CARBURETOR INSPECTION
1. Inspect jet needle and needle jet for wear. Look
for discoloration, shiny spots, or an area that
looks different than the rest of the needle. The
middle to upper portion of the needle contacts the
needle jet and is the most likely wear point. If jet
needle shows signs of wear replace both the
needle and needle jet to prevent a rich condition.
TIP: A worn needle jet is difficult to spot. To check,
slide a slightly larger new jet needle into the
needle jet and hold it to a light source. Light will be
visible between the needle and needle jet if it is
worn.
Jet Needle
Inspect this
area
2. Inspect the inlet needle tapered surface for any
sign of wear or damage. Be sure the spring
loaded pin is free moving and returns freely when
pushed. The inlet needle and seat should be
pressure tested after assembly.
Good Condition
Seat
Needle
4.10
Needle Jet
Worn, Deposits
Wear areas
CARBURETOR ASSEMBLY
Inspect the diaphragm (A) for holes, deterioration, or
damage. Make sure the diaphragm is pliable but not
swollen. The diaphragm should fit properly in the
carburetor body. Replace diaphragm assembly if
diaphragm is damaged.
3. Replace parts in proper order. The spring seat
washer (B) is stepped and must be placed on
TOP of "E" Clip (C). Spacer washer (D) must be
installed below the E-Clip. Refer to parts manual
for more information.
4. Be sure the tab (E) on outer edge of diaphragm is
positioned properly in the carburetor body.
Pilot Screw
C
B
D
A
E