Technical Tips; Carburetor - Yamaha FT50C Service Manual

Shift slider type shift mechanism
The FT50C has adopted the shift slider type shift mechanism. This shift mechanism enables a
prompt engagement of the dog clutch regardless of the operating speed of the shift lever. Thus,
smooth and positive shift operation has been made possible.
1 Shift rod
2 Propeller shaft
3 Dog clutch
4 Shift slider

Technical tips

Carburetor

Starting system (Prime Start)
To facilitate the starting of a cold engine, an air-fuel mixture that is richer than normal is required.
For this reason, the Prime Start system has been adopted in the FT50C. In the Prime Start system,
the thermo heater plunger is in a position that fully opens the fuel enrichment valve while the engine
is being started. Thus, fuel enrichment is achieved during the starting of the engine, and continues
while the engine is being warmed up. Once the engine starts, current flows from the lighting coil of
the to the thermo heater, allowing the wax in the Prime Start unit to expand. The expanded wax
moves the thermo heater plunger in the direction to close the enrichment valve. As a result, the vol-
ume of fuel that passes through the fuel enrichment valve decreases. A few minutes after the
engine has started, the thermo heater plunger completely closes the fuel enrichment valve, thus
ending the fuel enrichment by the Prime Start system.
62Y5A11
Features and benefits / Technical tips
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