Carburetor Tests And Adjustments; Inlet Valve Seat Inspection; Float Level Height Adjustment - Polaris 1999 Sportsman 400 Service Manual

186
C HAP T E R SIX
Inlet Vain Sea t Inspection
CARBURETO R TESTS AND
ADJ USTM ENTS
1. Float level gauge
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The fuel inlet valve is controlled by the float to
maintain a constant fuel level in the carburetor fl oat
bow l. Because the height of the fuel affects the
air/fuel mixture throughout the engine's operating
range. make sure the
float
position is correctly ad-
j usted.
l , Remove the carburetor as described in this chap-
ter.
2. Remove the mounting screws and remove the
float bowl and O-ring gasket (Figure 53).
3. Hold the carburetor on its side so the tang in the
midd le of the float ann is just touching the fuel
valve. Use a float level gauge, vernier caliper or
small ruler (Figure 54) and measure the distance
from the carburetor body gasket surface to the
float.
The correct distance is listed in Table 1.
4 .
If the
float setting is incorrect, adjust as follo ws:
a. Carefully bend the tang in the center of the
float arm (Figure 55) with a small screw-
driver to adjust the float level.
b. Recheck the floa t level as described in Step 3.
Rep eat until the flo at leve l adju stment is cor-
rect.
5. Install the O-ring seal (Figure 33) into the float
bowl and install the float bowl. Tighten the screws
securely.
6. Install the carburetoras described in this chapter.
Float Leve l Heigh t Adjustment
The float valve sealing ab ility can be checked
with a small hand-held pressure pump.
1. Turn the assembled carburetor upside down on
the top cover.
2. Attac h a small hand-held pressure pump to the
fuel inlet fitting (Fig ure 52).
3. Apply 34.5 kPa (5 psij of pressurc to the inlet fitting.
4. TI,e needle and seat should hold this pressure in-
definitely.
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5. If the need le and scat do no pass this test, replace
both parts.
6. Remove the hand-held pressure pump.