Yamaha MM700A, Manual, Page: 142 / 282

136 CHAPTER FIVE
10. Install the spring, washer and O-ring onto the pilot
mixture screw (Figure 39). Install the pilot mixture screw
into the carburetor body. Then back the screw out the
same number of turns noted during disassembly.
11. Install the starter assembly (Figure 40).
12. Install the throttle valve and inner throttle lever as-
sembly
(Figure 24). Align the jet needle with the needle
jet opening.
13. Center carburetor-perform the following:
a.
b.
Fuel
Install the throttle cable bracket Figure 22).
Install the TORS switch Figure 22) and spring.
Install the spring (25, Figure spring seat
screw washer washer (20) and nut (21) and
throttle stop screw (A, Figure 22). Rotate the stop
screw counterclockwise.
CARBURETOR ADJUSTMENTS
Level
The fuel level in the carburetor float bowl is critical to
proper performance. The fuel flow rate the bowl up
to the carburetor bore depends not only on the vacuum in
the throttle bore and the size of the jets, but also on the fuel
level. The actual fuel level, measured from the fuel level
in the float bowl to the centerline of the carburetor bore
with the carburetors installed,
is more useful than a simple
float height measurement because the actual fuel level can
vary from snowmobile to snowmobile even when the
floats are set at the same height. Refer to the tables located
at the end of this chapter.
1. Start the engine and run it until it reaches normal oper-
ating temperature.
Turn the engine off.
3. Place the snowmobile on a level surface.
4.
Attach a small, transparent hose to the float howl drain
fitting as shown in Figure 41. Hold the hose in a vertical
position.
5. Loosen the drain screw so fuel flows into the hose.
6. Start the engine and let it idle. Allow the fuel level to
stabilize in the hose.
7. Measure the distance from the fuel level in the hose to
the centerline of the carburetor bore (Figure 41).
8. Record the fuel level for each carburetor.
9. Refer to the specified fuel level in Table
1 or Table 2 at
the end of this chapter.
If the fuel level is not correct, re-
move the carburetors and adjust the float height as de-
scribed in this chapter.
10. Reinstall the carburetors and recheck the fuel level in
each carburetor.
Float Height Check and Adjustment
1. If not previously removed, remove the float bowl and
gasket as described in this chapter.
2. Invert the carburetor. Tilt the carburetor (Figure 42) so
the float arm just contacts the fuel valve, but does not
compress
spring-loaded plunger in the valve.
3. the float height as shown in Figure 42.
4. If the float height is incorrect. remove the float pin and
float. Bend the tang on the float that contacts the fuel
valve plunger.
Reinstall the float and pin. Recheck the float height.
6. Install the float bowl as described in this chapter.
CARBURETOR HEATING SYSTEM
Some models are equipped with a carburetor heating
system. Engine coolant is routed through hoses to the car-
buretors. Coolant heated by the engine, heats the carbure-
tors thereby improving carburetor operation and
preventing carburetor icing. A manual valve controls
coolant flow to the heating system. See Figure 43.
Repair any leak as soon as possible. Because the carbu-
retor heating system uses engine coolant, any leak