Effectivity 912/914 Series
Edition 1 / Rev. 0
page 25
May 01/2007
d02623
73-00-00
BRP-Rotax
Maintenance Manual
3.3.5) Diaphragm
See Figs. 73-15 and 73-16.
The plunger (carburetor piston) (8) is attached to the diaphragm (6).
Depending on the pressure prevailing, the plunger is moved up or
down. For inspection, remove the two counter sunk screws (1) M5x12,
take off the chamber top (2) and remove the plunger spring (3). Check
that the cover plate (4) on the chamber top is tightly seated. Wash
chamber top with cleaning agent and blowclean the inside venting bore
with compressed air Then carry out a visual inspection.
Pull carburetor piston out of the carburetor housing and remove the 4
allen screws (5) M4x12. The diaphragm (6) is held by the retaining ring
(7) on the carburetor piston (8). The position of the carburetor piston
is controlled via the diaphragm. There are 2 indexing tabs on the
diaphragm (5). Tab (9) fits exactly into the recess in the slider piston and
nose (10) must engage in the recess in the carburetor housing.
Check diaphragm for cracks or brittleness, replace if necessary.
3.3.6) Jet needle
See Fig. 73-16.
The jet needle (12) controls the fuel consumption at part load. It can be
regulated by selecting a jet needle position between 1 and 4. Modifica-
tions are allowed only after consultation with the engine manufacturer.
Unscrew the retaining screw (11), check jet needle (12) with shaft
securing (13) and O-Ring (20) for signs of wear.
Pay especial attention to the grooves and the taper of the needle. If
there is visible wear, the jet needle must be replaced and a new one
refitted in the same position.
â—† NOTE: The jet needle must move freely when fitted.
Carry out a visual inspection of the outer diameter of the carburetor
piston (8) and the two inside compensation bores.
â—† NOTE: The jet needle is damped by the O-ring (38).
See Figs. 73-13 and 73-14.
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