ENGINE FUEL PART 2

The fuel metering force of a conventional float-type carburetor in its normal operating range is the difference between the pressure acting on the discharge nozzle located within the venturi and the pressure. acting on the fuel in the float chamber. of the fuel as it enters the carburetor. of the air as it enters the venturi (impact pressure).

An aircraft should be facing into the wind when trimming an engine. However, if the velocity of the wind blowing into the intake is excessive, it is likely to cause a. false low exhaust gas temperature reading. trim setting resulting in engine overspeed. false high compression and turbine discharge pressure, and a subsequent low trim.

During what period does the fuel pump bypass valve open and remain open?. When the fuel pump pressure is greater than the demand of the engine. When the boost pump pressure is greater than fuel pump pressure. When the fuel pump output is greater than the demand of the carburetor.

What could cause a lean mixture and high cylinder head temperature at sea level or low altitudes?. Mixture control valve fully closed. Defective accelerating system. Automatic mixture control stuck in the extended position.

Kerosene is used as turbine engine fuel because. kerosene has very high volatility which aids in ignition and lubrication. kerosene has more heat energy per gallon and lubricates fuel system components. kerosene does not contain any water.

The fuel pump relief valve directs excess fuel to the. fuel tank return line. inlet side of the fuel pump. inlet side of the fuel strainer.

The primary condition(s) that allow(s) microorganisms to grow in the fuel in aircraft fuel tanks is (are). warm temperatures. the presence of water. the presence of dirt or other particulate contaminants.

Detonation occurs when the air-fuel mixture. burns too fast. ignites before the time of normal ignition. is too rich.

When troubleshooting an engine that will not idle, what would be a probable cause?. Economizer valve not operating correctly. Mixture setting too rich. Manifold valve is not operating properly.

Fuel boost pumps are operated. to provide a positive flow of fuel to the engine. during takeoff only. primarily for fuel transfer to another tank.

How will the mixture of an engine be affected if the bellows of the automatic mixture control (AMC) in a pressure carburetor ruptures while the engine is operating at altitude?. It will become leaner. No change will occur until the altitude changes. It will become richer.

The economizer system in a float-type carburetor. keeps the fuel/air ratio constant. functions only at cruise and idle speeds. increases the fuel/air ratio at high power settings.

An excessively lean air-fuel mixture may cause. an increase in cylinder head temperature. high oil pressure. backfiring through the exhaust.

An indication that the optimum idle mixture has been obtained occurs when the mixture control is moved to IDLE CUTOFF and manifold pressure. decreases momentarily and RPM drops slightly before the engine ceases to fire. increases momentarily and RPM drops slightly before the engine ceases to fire. decreases and RPM increases momentarily before the engine ceases to fire.

The metered fuel pressure (chamber C) in an injection-type carburetor. is held constant throughout the entire engine operating range. varies according to the position of the poppet valve located between chamber D (unmetered fuel) and chamber E (engine-driven fuel pump pressure). will be approximately equal to the pressure in chamber A (impact pressure).

It is desirable that fuel lines have a gentle slope upward or downward and not have sharp curves or sharp rises and/or falls in order to. prevent vapor lock. prevent stagnation or 'pooling' of fuel in the fuel lines. minimize the generation of static electricity by decreasing fluid friction in the lines.

Where is the throttle valve located on a float-type carburetor?. Between the venturi and the discharge nozzle. After the main discharge nozzle and venturi. After the venturi and just before the main discharge nozzle.

Reciprocating engine power will be decreased at all altitudes if the. air density is increased. humidity is increased. manifold pressure is increased.

The device that controls the volume of the air-fuel mixture to the cylinders is called a. mixture control. metering jet. throttle valve.

What method is ordinarily used to make idle speed adjustments on a float-type carburetor?. An adjustable throttle stop or linkage. An orifice and adjustable tapered needle. An adjustable needle in the drilled passageway which connects the airspace of the float chamber and the carburetor venturi.

Which of the following causes a single diaphragm accelerator pump to discharge fuel?. An increase in venturi suction when the throttle valve is open. An increase in manifold pressure that occurs when the throttle valve is opened. A decrease in manifold pressure that occurs when the throttle valve is opened.

If a float-type carburetor becomes flooded, the condition is most likely caused by. a leaking needle valve and seat assembly. the accelerating pump shaft being stuck. a clogged back-suction line.

What is a function of the idling air bleed in a float-type carburetor?. It provides a means for adjusting the mixture at idle speeds. It vaporizes the fuel at idling speeds. It aids in emulsifying/vaporizing the fuel at idle speeds.

When an electric primer is used, fuel pressure is built up by the. internal pump in the primer solenoid. suction at the main discharge nozzle. booster pump.

During idle mixture adjustments, which of the following is normally observed to determine when the correct mixture has been achieved?. Changes in fuel/air pressure ratio. Changes in RPM or manifold pressure. Fuel flowmeter.

What carburetor component measures the amount of air delivered to the engine?. Economizer valve. Automatic mixture control. Venturi.

In a supervisory EEC system, any fault in the EEC that adversely affects engine operation. causes redundant or backup units to take over and continue normal operation. usually degrades performance to the extent that continued operation can cause damage to the engine. causes an immediate reversion to control by the hydromechanical fuel control unit.

How often should float carburetors be overhauled?. At engine overhaul. Annually. At engine change.

Which of the following is NOT a function of the carburetor venturi?. Proportions the fuel/air mixture. Regulates the idle system. Limits the airflow at full throttle.

The fuel level within the float chamber of a properly adjusted float-type carburetor will be. slightly higher than the discharge nozzle outlet. slightly lower than the discharge nozzle outlet. at the same level as the discharge nozzle outlet.

Which of the following statements is true?. The mixture used at rated power in air cooled reciprocating engines is leaner than the mixture used through the normal cruising range. The mixture used at idle in air cooled reciprocating engines is leaner than the mixture used at rated power. The mixture used at idle in air cooled reciprocating engines is richer than the mixture used at rated power.

Fuel lines are kept away from sources of heat, and sharp bends and steep rises are avoided to reduce the possibility of. liquid lock. vapor lock. positive lock.

Fuel is discharged for idling speeds on a float-type carburetor. from the idle discharge nozzle. in the venturi. through the idle discharge air bleed.

An aircraft engine continuous cylinder fuel injection system normally discharges fuel during which stroke(s)?. Intake. Intake and compression. All (continuously).

If an engine equipped with a float-type carburetor backfires or misses when the throttle is advanced, a likely cause is that the. float level is too high. main air bleed is clogged. accelerating pump is not operating properly.