Repair Instructions
7.14 Carburettor
WARNING!
The fuel used in the chain saw has the following hazardous properties:
1.The fluid and its vapour are poisonous.
2.Can cause skin irritation.
3.Is highly inflammable.
Description
The figures accompanying this description do not correspond with the carburettor on the chain saw. They show only the principle of design and func- tion.
Design
The carburettor is based on three
• Metering unit, A.
• Mixing unit, B.
• Pump unit, C.
Fig 27 |
The needles and the fuel’s control functions are located in the metering unit, A. Here the correct quantity of fuel is adjusted for the actual speed and power output. See figure 27.
The mixing unit B houses the choke, the throttle valve and the diffuser jets. Here air is mixed with the fuel to give a fuel/air mixture that can be ignited by the ignition spark. See figure 28.
In the pump unit C, fuel is pumped from the fuel tank to the carburettor’s metering unit. One side of the pump diaphragm is connected to the crankcase and pulses in time with the pressure changes in the crankcase. The other side of the diaphragm pumps the fuel. See figure 29.
B
Fig 28
Fig 29 |
34 - English