Yamaha F25 Service Manual page 42

TECH
FEA
Technical features and description
Engine control system
Outline ........................................................................................ 2-1
Ignition control system
Ignition timing control ................................................................. 2-3
Basic ignition timing control........................................................ 2-4
Starting ignition timing control .................................................... 2-4
Acceleration ignition timing control............................................. 2-5
Cold and warm engine ignition timing control............................. 2-6
Engine speed control.................................................................. 2-7
Engine speed control during over-revving.................................. 2-7
Engine speed control during overheating................................... 2-7
Engine speed control during low oil pressure............................. 2-7
Power unit
..................................................................................... 2-8
Outline ........................................................................................ 2-8
Balancer ..................................................................................... 2-9
Automatic decompression device (manual starter model) ......... 2-9
Lubrication system
System diagram ....................................................................... 2-10
Cooling system
System diagram ....................................................................... 2-11
Intake and exhaust system
System diagram ....................................................................... 2-12
Carburetor
Prime Start system ................................................................... 2-13
Acceleration pump.................................................................... 2-14
PTT unit
....................................................................................... 2-15
Outline ...................................................................................... 2-15
Tilt up operation........................................................................ 2-16
Tilt down operation ................................................................... 2-17
Operation during malfunctions ................................................. 2-18
When the outboard motor hits something in the water............. 2-18
.............................................................. 2-1
............................................................. 2-3
.................................................................. 2-10
......................................................................... 2-11
.................................................... 2-12
.................................................................................. 2-13
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