Specifications; Engine; Fuel System; Ignition System - Stihl MS 661 Manual

2.

Specifications

2.1

Engine

Displacement:
Bore:
Stroke:
Engine power to ISO 7293:
Max. permissible speed (with cutting
1)
attachment):
Idle speed:
Clutch:
Clutch engages at:
Crankcase leakage test
at gauge pressure:
under vacuum:
2.2

Fuel System

2.3

Ignition System

2.4

Chain Lubrication

Standard / Uprated
Standard
Uprated
(with pin driven home)
1) The engine reaches its maximum RPM and maximum power after the break-in period (5 to 10 tank fillings) –
do not make any changes to the high speed screw (H) during the break-in period.
MS 661, MS 661 C-M
MS 661, MS 661 C-M
91.1 cc
56.0 mm
37.0 mm
5.4 kW (7.4 bhp) at 9,500 rpm
1)
13,500 rpm
2,800 rpm
Centrifugal clutch without linings
4,080 rpm
0.5 bar
0.5 bar
Carburetor leakage test at
gauge pressure:
Operation of tank vent at
gauge pressure:
Fuel:
Air gap between ignition
module and fanwheel:
Spark plug (resistor type):
Electrode gap:
Speed-controlled oil pump with reciprocating piston and
manual flow control
Settings for oil delivery rate:
0.8 bar
0.5 bar
see instruction manual
0.30 (+ 0.05 / - 0.10) mm
NGK BPMR 7 A
BOSCH WSR 6 F
0.5 mm
min.: 7.0 (+/- 2.8) cc/min
at 7,000 rpm
max.: 14.3 (+/- 2.5) cc/min
at 7,000 rpm
max.: 18.9 (+/- 2.5) cc/min
at 7,000 rpm
5