Yamaha F25 - Power Unit Technical Data

1-13
SPEC
Specification
Power unit technical data
Power unit
Fuel pump
Holding pressure
Inlet positive pressure
kPa
(kgf/cm
2
,
psi)
50.0 (0.50, 7.3)
Inlet negative pressure
kPa
(kgf/cm
2
,
psi)
30.0 (0.30, 4.4)
Outlet positive pressure
kPa
(kgf/cm
2
,
psi)
50.0 (0.50, 7.3)
Carburetor
Float height mm (in) 14.0 ± 2.0 (0.55 ± 0.08)
Valve seat size mm (in) 1.2 (0.05)
Main jet (MJ) #108
Main air jet (MAJ) #70
Main nozzle (MN) mm (in) 2.6 (0.10)
Pilot jet (PJ) #45
Pilot air jet (PAJ) #85
Starter jet (SJ) #62
Prime Start plunger length mm (in) 10.7 (0.42)
Item
Unit
Model
F25MHA
F25EHA
Cylinder
Minimum compression
pressure (*1)
kPa
(kgf/cm
2
,
psi)
750.0 (7.50, 108.8) 870.0 (8.70, 126.2)
Engine oil
Oil pressure (*2)
at 60 °C (140 °F) with SL
10W-30 engine oil and at
950 r/min
kPa
(kgf/cm
2
,
psi)
250.0 (2.50, 36.3)
Thermostat
Valve opening temperature
°C (°F) 58.0–62.0 (136–144)
Fully open temperature
°C (°F) 70.0 (158)
Fully open stroke
mm (in) 3.0 (0.12)
Item Unit
Model
F25EA
F25A T25A
Cylinder
Minimum compression
pressure (*1)
kPa
(kgf/cm
2
,
psi)
870.0 (8.70, 126.2)
Item Unit
Model
F25EA
F25A T25A