Free Practice Questions for Craftsman Excavator Operator

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Key Facts: Craftsman Excavator Operator Exam

60 items

Written CBT question count

Q-Net examination standard for 굴착기운전기능사 (2025-2027)

60 minutes

Written CBT examination time limit

Q-Net examination standard for 굴착기운전기능사 (2025-2027)

60 / 100

Passing score for written (36/60 items) and practical

National Technical Qualifications Act Enforcement Rules

KRW 14,500

Written examination fee

Q-Net examination fee schedule (2026)

KRW 27,800

Practical examination fee

Q-Net examination fee schedule (2026)

2 years

Written test exemption period

National Technical Qualifications Act Enforcement Decree Article 21

about 15 minutes

Duration of the work-type practical test

Q-Net examination standard for 굴착기운전기능사 (2025-2027)

굴착기운전기능사 is HRD Korea's craftsman-grade excavator qualification, with the Ministry of Land, Infrastructure and Transport as competent ministry. The 60-minute written CBT is 60 four-option items (pass mark 60/100) on one merged subject, 굴착기 조종, 점검 및 안전관리. The practical is a work-type test in 굴착기 조종 실무 of about 15 minutes. Fees are KRW 14,500 written and KRW 27,800 practical on Q-Net. OpenExamPrep provides independent English MCQ practice, not an official translation or a machine control simulation.

Sample Craftsman Excavator Operator Practice Questions

Try these sample questions to review concepts for the Craftsman Excavator Operator exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1In a 4-stroke diesel engine used in heavy construction equipment, what is the correct operational sequence of the cycle and the total crankshaft rotation required to complete it?

A.Intake → Power → Compression → Exhaust, completing in 360° of crankshaft rotation

B.Intake → Compression → Power → Exhaust, completing in 720° of crankshaft rotation

C.Compression → Intake → Power → Exhaust, completing in 540° of crankshaft rotation

D.Intake → Compression → Exhaust → Power, completing in 720° of crankshaft rotation

Explanation: A 4-stroke diesel engine operates through the sequence of Intake (흡입), Compression (압축), Power/Combustion (폭발/동력), and Exhaust (배기). Each piston stroke corresponds to 180° of crankshaft rotation, meaning all four strokes require two full revolutions (720°) to complete one thermodynamic cycle.

2What is the typical compression ratio (압축비) range for direct-injection industrial diesel engines commonly fitted on excavators?

A.6:1 to 10:1

B.10:1 to 14:1

C.15:1 to 22:1

D.25:1 to 35:1

Explanation: Industrial direct-injection diesel engines rely on compression heat to self-ignite atomized diesel fuel and operate with compression ratios typically between 15:1 and 22:1. This produces compression pressures of 30 to 45 kgf/cm² and air temperatures exceeding 500°C to 700°C, ensuring reliable auto-ignition.

3When performing fuel system air bleeding (연료계통 공기빼기) on an excavator equipped with an in-line or distributor mechanical injection pump, what is the correct bleeding order?

A.Fuel sedimenter/filter priming pump bleed screw → Injection pump bleed screw → High-pressure injection pipes at injectors

B.High-pressure injection pipes at injectors → Injection pump bleed screw → Fuel filter priming pump bleed screw

C.Injection pump bleed screw → Fuel tank drain cock → Low-pressure fuel filter priming pump

D.High-pressure injection pipes at injectors → Fuel tank vent valve → Feed pump priming button

Explanation: Air bleeding must follow the direction of fuel flow from the low-pressure side to the high-pressure side. The technician operates the priming pump to bleed air at the fuel filter/water separator air vent screw first, then at the injection pump bleeder screw, and finally cranks the engine with the high-pressure injector nuts loosened until bubble-free fuel squirts out.

4What is the primary function of the fuel-water separator (유수분리기, sedimenter) installed between the fuel tank and feed pump on an excavator?

A.To increase fuel delivery pressure before entering the high-pressure fuel rail

B.To vaporize residual moisture using electric heating coils during engine operation

C.To mix fuel additives evenly with incoming diesel fuel

D.To separate moisture and coarse contaminants from diesel fuel based on density differences

Explanation: Water has a higher specific gravity (approx. 1.0) than diesel fuel (approx. 0.83–0.85). The fuel-water separator uses this density difference and internal baffles/filter media to collect moisture and coarse sediment at the bottom of a transparent sediment cup, preventing corrosion and seizing in high-precision fuel injection components.

5In an excavator Common Rail Direct Injection (CRDi) system, which statement accurately describes the main advantage of the common rail accumulator over conventional mechanical injection pumps?

A.It eliminates the need for an engine electronic control unit (ECU) by using purely mechanical pressure balance

B.It maintains ultra-high injection pressure regardless of engine RPM and permits precise multi-stage injection

C.It allows the engine to run without a fuel filter or fuel water separator

D.It reduces fuel injection pressure during high-load digging to avoid hydraulic interference

Explanation: In CRDi systems, the high-pressure pump continuously pressurizes fuel into an accumulator rail (1,600 to 2,500 bar) independent of engine speed. The Engine Control Unit (ECU) actuates solenoid or piezoelectric injectors to perform flexible multi-stage injection (pilot, pre, main, post), significantly optimizing combustion efficiency, torque, noise, and exhaust emissions.

6What operational symptom is most commonly observed when air is trapped in the low-pressure or high-pressure fuel lines of an excavator diesel engine?

A.Coolant temperature drops rapidly and white steam vents from the radiator cap

B.Engine oil viscosity increases immediately and the oil level rises above the full mark

C.Hard starting, severe engine surging, rough idle, or unexpected engine stalling

D.Hydraulic pump displacement increases automatically and relief pressure doubles

Explanation: Because air is highly compressible compared to liquid diesel fuel, trapped air bubbles absorb the pumping stroke of the feed pump and high-pressure injection plungers. This leads to erratic fuel delivery, delayed injection timing, misfiring, rough idling, hesitation under load, or complete failure to start.

7What is the primary function of the oil pressure relief valve (유압조절밸브) located in the engine lubrication circuit?

A.To prevent excessive oil pressure buildup at high engine speeds by returning surplus oil to the oil pan

B.To shut off oil flow completely whenever the engine is idling to conserve lubrication energy

C.To divert hot oil directly into the combustion chamber to reduce exhaust opacity

D.To measure engine oil temperature and activate the cooling fan clutch

Explanation: The engine oil pump is driven directly by the crankshaft or camshaft, so its discharge volume and pressure rise sharply as engine speed increases. The spring-loaded oil pressure relief valve opens when circuit pressure reaches a preset limit (typically 3 to 5 kgf/cm²), bypassing excess oil back to the oil pan or pump inlet to protect seals, filters, and galleys from rupture.

8In an excavator engine lubrication circuit, what safety feature ensures that engine bearings continue receiving oil if the full-flow oil filter element becomes completely clogged?

A.The oil pump reverses rotation to backflush the clogged filter media

B.The engine emergency stop solenoid shuts down the engine instantly within 1 second

C.The fuel injection pump reduces delivery volume by 50% into limp-home mode

D.A filter bypass valve (바이패스 밸브) opens under differential pressure to supply unfiltered oil to main galleries

Explanation: A full-flow oil filter housing incorporates a spring-loaded bypass valve (바이패스 밸브). When the filter element is obstructed by sludge or heavy debris, the differential pressure across the element overcomes the valve spring (typically 1.0 to 1.5 kgf/cm²), routing unfiltered oil directly to the main oil gallery. Unfiltered oil is considered preferable to total oil starvation, which would seize the crankshaft and connecting rod bearings within seconds.

9Which of the following conditions is the most direct cause of low engine oil pressure when an excavator diesel engine is running at operating temperature?

A.Using engine oil with an excessively high viscosity rating (e.g., SAE 50 in winter)

B.Excessive clearance in crankshaft main and rod bearings, or a relief valve stuck open

C.Overfilling the crankcase with 10% fresh engine oil above the maximum line

D.A fully closed thermostat preventing coolant flow through the engine block

Explanation: Engine oil pressure is generated by the resistance of calibrated clearances against oil pump flow. Excessive clearances in the crankshaft main bearings, connecting rod journals, or camshaft bushings allow oil to escape freely back into the pan, causing low pressure. Similarly, a pressure relief valve stuck open by debris dumps pump flow prematurely.

10In the multi-grade engine oil classification 'SAE 15W-40' commonly specified for excavator diesel engines, what does the '15W' signify?

A.Low-temperature cold cranking and pumpability viscosity grade ('W' stands for Winter)

B.The percentage of detergent-dispersant additives contained within the engine oil formulation

C.The high-temperature shear stability rating at an engine operating temperature of 150°C

D.The minimum flash point temperature of the lubricating oil measured in degrees Celsius

Explanation: In SAE multi-grade designations, the number preceding the letter 'W' (Winter) denotes low-temperature fluidity and cold-crank capability. A lower winter number (e.g., 5W or 10W vs 15W) indicates better flow at freezing ambient temperatures during cold starting, whereas the second number (40) reflects kinematic viscosity measured at 100°C.

About the Craftsman Excavator Operator Exam

Craftsman Excavator Operator (굴착기운전기능사, renamed from 굴삭기운전기능사) is a national technical qualification administered by HRD Korea through Q-Net, with the Ministry of Land, Infrastructure and Transport as the competent ministry. The written paper is a single merged subject, 굴착기 조종, 점검 및 안전관리, built from six main items: inspection, travelling and working, structure and function, safety management, the Construction Machinery Management Act and Road Traffic Act, and machine structure. It is examined on a continuous (상시) schedule rather than in a handful of annual sittings. Passing the written paper leads to a work-type practical test in 굴착기 조종 실무. Note that the certificate alone does not authorise site operation: a Construction Machinery Operator License must then be issued by the local authority. OpenExamPrep provides an independent English-language MCQ study adaptation; it is not an official translation and it does not simulate machine control.

Exam sponsor: HRD Korea (Q-Net) / Ministry of Land, Infrastructure and Transport (MOLIT). The requirements and fees below concern the certification or admission exam, separate from our free practice resources.

Assessment

Written examination of 60 four-option CBT questions in 60 minutes on the single official subject 굴착기 조종, 점검 및 안전관리, followed by a work-type practical test in 굴착기 조종 실무 of about 15 minutes covering machine trial running, travelling, trenching, cutting, stockpiling, backfilling, attachment work, pre- and post-operation checks and safety.

Time Limit

60 minutes written; approx. 15 minutes practical

Passing Score

Written: 60/100 (36/60); practical: 60/100

Exam / Certification Fees

KRW 14,500 written / KRW 27,800 practical (Q-Net, 2026)

Exam sponsor website

Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.

Official sources

Q-Net qualification detail page for Craftsman Excavator Operator (굴착기운전기능사) · Source checked 2026-09-21Official qualification record: written subject, practical subject, fees and sitting schedule.
Q-Net examination standard for 굴착기운전기능사 (출제기준, 2025.1.1-2027.12.31) · Source checked 2026-09-21Single written subject 굴착기 조종, 점검 및 안전관리 with main items 점검, 주행 및 작업, 구조 및 기능, 안전관리, 건설기계관리법 및 도로교통법, 장비구조; practical subject 굴착기 조종 실무.
Enforcement Rules of the National Technical Qualifications Act, Table 8 (국가기술자격법 시행규칙 [별표 8]) · Source checked 2026-09-21Statutory subjects: 필기시험 굴착기 조종, 점검 및 안전관리 / 실기시험 굴착기 조종 실무.
Construction Machinery Management Act (건설기계관리법) · Source checked 2026-09-21Registration, plate colours (Enforcement Rules Table 2), inspections, operator licensing and penalties used in this bank.
Rules on Occupational Safety and Health Standards (산업안전보건기준에 관한 규칙) · Source checked 2026-09-21Article 322 machine clearance from live conductors, and excavation/trench safety duties.

Our practice resources: topics covered

We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.

Main item

Inspection (점검)

Pre- and post-operation checks: engine oil, coolant and antifreeze, fuel and water separator, air cleaner servicing, fan belt tension, track tension and daily greasing of front attachment pins.

Main item

Travelling and Working (주행 및 작업)

Travelling up and down grades with the sprockets downhill, why side-hill traverse is prohibited, trenching and spoil placement, parking procedure and loading for transport.

Main item

Structure and Function (구조 및 기능)

Four-stroke diesel cycle, compression ratio, cooling and lubrication circuits, intake, turbocharging and aftertreatment, battery, alternator and starter operation.

Main item

Machine Structure (장비구조)

Idler, recoil spring, rollers, sprocket and track wear measurement, swing bearing, centre joint, boom/arm/bucket linkage, hydraulic pumps, main and port relief valves, cylinders and motors.

Main item

Safety Management (안전관리)

Baseline PPE, three-point contact, swing-radius barricading, trench cave-in warning signs and spoil setback, buried gas and power line marking, hand digging near pipelines, and clearance from live overhead lines.

Main item

Construction Machinery Management Act and Road Traffic Act (건설기계관리법 및 도로교통법)

Registration plate colours, change registration, periodic and structural alteration inspections, temporary operation permits, operator licence penalties and revocation, oversize transport permits and level-crossing procedure.

Preparing for the Craftsman Excavator Operator Exam

What You Need to Know

Passing score: Written: 60/100 (36/60); practical: 60/100
Assessment: Written examination of 60 four-option CBT questions in 60 minutes on the single official subject 굴착기 조종, 점검 및 안전관리, followed by a work-type practical test in 굴착기 조종 실무 of about 15 minutes covering machine trial running, travelling, trenching, cutting, stockpiling, backfilling, attachment work, pre- and post-operation checks and safety.
Time limit: 60 minutes written; approx. 15 minutes practical
Exam / certification fees: KRW 14,500 written / KRW 27,800 practical (Q-Net, 2026) Official sources

Using Our Practice Resources

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Craftsman Excavator Operator: Suggested Study Strategy

1Treat the paper as one merged subject: the official standard lists 점검, 주행 및 작업, 구조 및 기능, 안전관리, 건설기계관리법 및 도로교통법 and 장비구조 as main items, not as separately weighted papers.

2Learn the inspection numbers that recur: fan belt deflection of 13-20 mm under about 10 kgf, antifreeze mixed roughly 50:50, and the fuel bleeding order from the low-pressure side toward the injectors.

3Master the hydraulic fundamentals: Pascal's law (P = F/A), cylinder speed v = Q/A, the role of the main relief valve versus port relief valves, and the causes of cavitation.

4Learn the undercarriage as a system: idler and recoil spring absorb shock, grease adjusts track tension, and pitch elongation across several links is how pin and bushing wear is measured.

5Memorise the statutory facts: orange plates with black characters for rental-business machines, 30 days for change registration, 15 days for a temporary operation permit, and safety education every 3 years.

6Know the buried utility colours - yellow for city gas, red for high-voltage power - and the rule that excavation within 1 m of a marked gas pipe must be done by hand.

7Learn the Korean equipment terms alongside the English principles, because the official Q-Net CBT is delivered in Korean.

Frequently Asked Questions

What is Craftsman Excavator Operator (굴착기운전기능사)?

It is South Korea's national technical qualification for operating hydraulic excavators, administered by HRD Korea via Q-Net under the Ministry of Land, Infrastructure and Transport (MOLIT). It certifies technical knowledge of excavator mechanics, hydraulics, legal regulations, and safe operation.

Who is eligible to sit the examination?

There are no prerequisites. As a Craftsman (기능사) grade qualification under the National Technical Qualifications Act, anyone can register regardless of educational background, major, or previous operating experience.

What is the examination structure and passing grade?

The written exam is a 60-minute CBT with 60 four-option multiple-choice questions on the single official subject 굴착기 조종, 점검 및 안전관리, whose main items are 점검, 주행 및 작업, 구조 및 기능, 안전관리, 건설기계관리법 및 도로교통법 and 장비구조. The passing score is 60 out of 100 (at least 36 correct answers). The practical exam is a work-type test in 굴착기 조종 실무 of about 15 minutes, also requiring 60 points or more out of 100.

What are the fees and written pass exemption rules?

The official Q-Net fees are KRW 14,500 for the written CBT and KRW 27,800 for the practical exam. Passing the written examination grants a two-year exemption from retaking the written test.

Can I operate an excavator on a job site immediately upon passing?

No. Under the Construction Machinery Management Act, after obtaining the national technical qualification certificate from HRD Korea, you must submit your certificate, physical aptitude check, and driver's license to your local municipal authority (시·군·구청) to be issued a Construction Machinery Operator License (건설기계조종사면허) before legally operating on site.