Diamond DA 40 Flight Manual page 248

Airplane
Description
The propeller governor is flanged onto the front of the engine. It regulates the supply of
engine oil to the propeller. The propeller governor oil circulation is an integral part of the
engine oil circulation system. Following a defect in governor or oil system, the blades go
the finest possible pitch (maximum RPM), thus allowing continuation of the flight.
Following failure of the governor or a serious drop in oil
pressure, the RPM should be adjusted using the throttle.
Every effort should be made not to exceed 2700 RPM.
The throttle and RPM lever should be moved slowly, in order
to avoid over-speeding and excessively rapid RPM changes.
The light wooden propeller blades produce more rapid RPM
changes than metal blades.
Mixture Control Lever
- Right hand lever with red handle and lock to avoid inadvertent operation.
This lever is used to set the proportions in the fuel-air mixture which is supplied to the
engine.
If the lever is at the forward stop, extra fuel is being supplied to the engine which at higher
performance settings contributes to engine cooling.
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CAUTION
CAUTION
Lever forward (RICH) = Mixture rich (in fuel)
Lever to rear (LEAN) = Mixture lean (in fuel)
Rev. 8 01-Dec-2010
DA 40 AFM
Doc. # 6.01.01-E