- Robin Industrial Engine Service Manual

9-1-2 PILOT SYSTEM
This pilot system feeds fuel to engine during idle and low speed operation.
The fuel fed through main jet
(MI) is measured by pilot jet (PJ), mixed with air measured by pilot air jet (PAJ), regulated by
pilot screw, and then fed
to engine through pilot outlet (PO) and bypass (BP).
The fuel is mainly fed from pilot outlet
(PO) during idling.
9-1-3 MAIN SYSTEM
This system feeds fuel to engine during medium and high-speed operation.
The air measured by main air jet
(MAJ) is mixed into fuel through bleed holes of main nozzle (MN) and discharged to main
bore (MB) as atomized fuel where it
is mixed with intake air through air cleaner to become an optimum air-fuel mixutre to
be supplied to engine.
9-1-4 CHOKE SYSTEM
The choke system serves to facilitate start-up in cold season. When engine is cranked with choke (C) closed, the negative
pressure to main nozzle
(MN) increases to introduce fuel in large quantities to make start-up easy.
9-2 DISASSEMBLY and REASSEMBLY
Besides mechanical ,failures, most troubles are caused by
incorrect mixing ratio.
The most common causes of such incorrect fuel-air mix-
tures are clogged jets, restricted air and fuel passages, and
variations in fuel level. In order to obtain the full
performance
of carburetor, it is necessary to keep air
cleaner and carburetor clean
so that air and fuel flow
without any restriction.
Observe following disassembly and reassembly procedures.
(See
Fig. 9-2)
9-2-1 THROTTLE SYSTEM
1) Remove Philipsscrew (1 1 ), remove throttle valve (1 5),
and then pull out throttle shaft (1 6).
2) Detach spring (7) by unscrewing throttle stop screw
(8).
9-2-2 CHOKE SYSTEM
1) Unscrew Philipsscrew (1 l), remove choke valve (9),
pull out choke shaft (IO), and then remove choke ball
(1 2) and choke spring (1 3).
2) When reassembiing choke shaft, place the notch of
choke valve on main air jet side.
5
7
6
1
7
8
25
24
-23-
Fig. 9-2