Chapter 2 Engine operation, instruments, maintenance, and overhaul

What indications are given in the event of a leaking or open primer while the engine is running?

The engine will not idle properly.

What does a cold cylinder indicate when troubleshooting a running engine?

No combustion in that cylinder.

What should be performed next if a hissing sound is heard when pulling a propeller through, indicating valve blow-by?

A compression check should be performed to identify the faulty cylinder.

What is the purpose of performing a compression test?

To determine if the valves, pistons and rings are sealing properly.

How is the total time on an engine affected when it is overhauled?

The total time on the engine must be continued and the time since major overhaul is entered into the engine log.

What happens to an engine's operating history when it is rebuilt by the manufacturer?

It is granted a zero-time status and is considered to have no previous operating history.

What inspections should be performed after a propeller strike without sudden stoppage?

1. Inspect engine mounts, the crankcase, and the nose section for damage. 2. Inspect the oil and oil filters/screens for metal particles. 3. Inspect the crankshaft or driveshaft for cracks and misalignment.

What precautions should be performed prior to engine removal?

Disconnect the battery, turn off the fuel valves, chock the wheels, and if necessary, install a tail stand.

Where are cracks most likely to be found when inspecting a piston?

In areas that are highly stressed; usually the base of the piston bosses, inside at the junction of the bore and the walls, and the ring lands.

What does it mean if an engine part is within 'serviceable limits'?

It means that the part is within the manufacturer's limits and can be used in an engine (does not require replacement).

What tools or instruments are used to inspect a cylinder barrel for out-of-roundness?

A dial indicator or an inside micrometer is usually used to measure the top of the cylinder and at the skirt. A telescopic gauge and micrometer can also be used.

How can a loose stud in an engine crankcase be repaired?

Remove the loose stud and inspect the hole for size and thread condition. It may be necessary to use an oversize stud or Heli-Coil® insert.

What publication is used to check an engine for normal operation?

Manufacturer's maintenance manual.

What must be inspected if a weak cylinder is found during a compression check?

Pressure is transmitted equally in all directions.

What purpose does an oil analysis serve?

Metal particles in the oil show normal and abnormal wear of the engine, helping to evaluate the engine's internal condition.

What inspection should be performed on an engine that has been in storage?

Perform an inspection to determine if there is any corrosion damage.

Where would a carburetor air temperature bulb be located?

In the ram air intake duct.

What is the fuel pressure range on float-type carburetors?

3 to 5 psi.

What are the basic components of a fuel indicator system?

The transmitter and the indicator.

What unit of measure is generally used to indicate fuel flow?

Pounds or gallons per hour.

Why is fuel flow monitored?

To determine fuel consumption and engine performance.

What does the manifold gauge indicate and how is it calibrated?

It measures the absolute pressure in the engine manifold and is calibrated in inches of mercury.

What directly controls manifold pressure?

Throttle opening and engine r.p.m.

Where should the propeller control be set when checking the manifold pressure?

Low pitch, high r.p.m.

Is the aircraft electrical system required to power a cylinder head temperature gauge?

No. A thermocouple is used as the electrical source.

What are the possible indications of an oil pressure transmitter or indicator malfunction?

A severe or sudden drop in oil pressure while the oil temperature remains normal and the oil supply remains full.

What does a tachometer indicate on a reciprocating engine?

Engine r.p.m.

Where should the thermocouple be installed on a reciprocating engine using a single probe cylinder head temperature system?

On the hottest cylinder.