Echo PB-251, Service Data

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SERVICE INFORMATION
PB-251
PB-255ES
ES-255ES
3
1-2 Technical data
Model PB-251 PB-255ES ES-255ES
Engine
Idling speed r/min 2800 - 3400* 2700 - 3300* 2500 - 3100**
Wide open throttle speed r/min 7200 - 7500* 6000 - 6500**
Compression pressure MPa (kgf/cm
2
) (psi) 0.87 (8.9) (126)
Ignition system
Spark plug gap
mm (in) 0.6 - 0.7 (0.024 - 0.028)
Minimum secondary voltage at 1500 r/min kV 15
Primary coil resistance Ω 160 - 400
Secondary coil resistance k Ω 2.5 - 3.2
Pole shoe air gaps mm(in) 0.3 - 0.4 (0.012 - 0.016)
Ignition timing at 1000 r/min °BTDC 7
at 3000 r/min °BTDC 18
at 7000 r/min °BTDC 31
Carburettor
Idle mixture needle initial setting turns back 4 1/8
H mixture needle initial setting turns back 7/8
Idle adjust screw initial setting turns back 1 5/8
Test Pressure, minimum MPa (kgf/cm
2
) (psi) 0.05 (0.5) (7.0)
Metering lever height mm (in) 0.1 - 0.25 (0.004 - 0.010) lower than diaphragm seat
BTDC: Before top dead centre.
*With fan head blower pipe.
** With vacuum pipe and bag.