73-00-00
page 16
October 01/2010
Effectivity 912/914 Series
Edition 1 / Rev. 3
d04777
BRP-Powertrain
Maintenance Manual
◆
NOTE:
On newer engines the manifold pressure fitting is plugged with
a M 3.5 screw. Remove this screw before attaching a manifold
pressure hose. See therefore SI-912-020 and SI-914-022 “run-
ning modifications” respectively.
2.11) Carb heat system and winter operation
The risks of carburetor icing are commonly known. The icing of air humidity in
the carburetor may be avoided by preheating the air.
◆
NOTE:
An airbox with a carburetor preheating flap is available for
engines of the 912 Series.
◆
NOTE:
Engines of the 914 Series normally do not require any preheating
device as the intake air is preheated by the turbocharger.
◆
WARNING: Carburetor icing is a common cause of engine faults.
Because of the heating up of intake air due to the boost process,
preheating of the intake air might not be necessary. But the
option of a change over for air intake from the engine compart-
ment is recommended as, for instance, the filter could be
blocked by icing.
Preheating of the intake air will result in loss of engine perform-
ance because of the reduction in air density.
A further measure to reduce the risk of carburetor icing is to keep the water
content of the fuel low by proper handling. Also, install a generously dimensioned
water trap in the fuel system of the aircraft to prevent the formation of ice in the
fuel lines, filters etc.
3) Maintenance
The following sections describe maintenance procedure for engines of the 912/914
Series above and beyond the maintenance and special checks, see corresponding
Maintenance Manual (Line Maintenance) for the respective engine type, 912 Series or
914 Series, and the systems descriptions given hitherto. The description is divided into
subsections and descriptions of the function of the various systems.
3.1)
Disassembling fuel pump, carburetors, carburetor sockets, fuel lines
and drip tray (on the 912 Series)
See Fig. 73-9, 73-9/1 and 73-9/2.
■
CAUTION: When disassembling the fuel lines support them so that tension
or additional strain is avoided.
Summary of Contents for MMH-912 Series
Page 463: ......
