Common Malfunctions of Single-Cylinder Air-Cooled Diesel Engines

Single-cylinder air-cooled diesel engines are widely used in agricultural machinery, power generation equipment, small ships, and other fields due to their simple structure, high reliability, and low maintenance costs. However, long – term use or improper operation may lead to various malfunctions, affecting equipment performance and even causing downtime. As a professional brand in the diesel engine field, SR POWER summarizes the ten common malfunctions of single – cylinder air – cooled diesel engines and their quick diagnosis methods based on years of technical experience. This helps users solve problems efficiently and extend the service life of the equipment.

1. The engine fails to start

Possible causes:

• Fuel system issues: Fuel exhaustion, blocked fuel lines, or dirty fuel filters.
• Air entering the fuel system: Loose connections or poor seals in the fuel pipes.
• Starting system failures: Insufficient battery power, damaged starter motors, or poor electrical contacts.
• Low compression pressure: Worn piston rings, damaged cylinder gaskets, or poor valve seals.

Quick diagnosis:

• Check the fuel tank level and the fuel line for blockages.
• Bleed the air from the fuel system (loosen the fuel pipe joint and manually pump the fuel until there are no bubbles).
• Check the battery voltage and whether the starter motor is working properly.
• Measure the cylinder compression pressure with a pressure gauge to see if it is within the normal range (usually 25 – 35 bar).

2. The engine has insufficient power

Possible causes:

• Insufficient fuel supply: Blocked injectors, low fuel pump pressure, or clogged fuel filters.
• Intake system problems: Dirty air filters or air leaks in the intake pipes.
• Incomplete combustion: Incorrect injection timing or low cylinder compression pressure.
• Poor heat dissipation: Excessive dust on the radiator fins, causing the engine to overheat.

Quick diagnosis:

• Check whether the fuel filter and injectors are blocked.
• Clean or replace the air filter and check the tightness of the intake pipes.
• Adjust the injection timing to ensure accurate fuel injection.
• Clean the radiator fins to ensure the normal operation of the air – cooling system.

3. The engine emits black smoke

Possible causes:

• Incomplete fuel combustion: Poor injector atomization or excessive fuel injection.
• Insufficient air intake: Blocked air filters or air leaks in the intake pipes.
• Overload: The engine is operating under excessive load.

Quick diagnosis:

• Check whether the injectors are damaged or blocked. Clean or replace them if necessary.
• Clean the air filter and check for air leaks in the intake pipes.
• Reduce the load to avoid long – term overloading of the engine.

4. The engine emits white smoke

Possible causes:

• Water in the fuel: Water in the fuel tank or a malfunctioning fuel filter.
• Water in the cylinder: Damaged cylinder gaskets or cracked cylinder heads.
• Incorrect injection timing: Premature fuel injection.

Quick diagnosis:

• Check if there is water in the fuel and replace the fuel if necessary.
• Check whether the cylinder gaskets and cylinder heads are damaged. Replace them if necessary.
• Adjust the injection timing to ensure accurate fuel injection.

5. The engine overheats

Possible causes:

• Cooling system problems: Excessive dust on the radiator fins or damaged fans.
• Poor lubrication: Insufficient engine oil or clogged oil filters.
• Overload: The engine is operating under excessive load for a long time.

Quick diagnosis:

• Clean the radiator fins and check whether the fan is working properly.
• Check the engine oil level and filter. Replace the engine oil if necessary.
• Reduce the load to avoid long – term overloading of the engine.

6. The engine makes abnormal noises

Possible causes:

• Wear of mechanical components: Worn piston rings, connecting rod bearings, or crankshaft bearings.
• Excessive valve clearance: Incorrect valve adjustment or damaged valve springs.
• Abnormal fuel injection: Poor injector atomization or high injection pressure.

Quick diagnosis:

• Check whether the piston rings, connecting rod bearings, and crankshaft bearings are worn. Replace them if necessary.
• Adjust the valve clearance to the specified value (usually 0.2 – 0.4 mm).
• Check the injectors and fuel pump to ensure normal fuel injection.

7. The engine oil pressure is too low

Possible causes:

• Insufficient engine oil: Low oil level or oil leakage.
• Oil pump failure: Worn oil pumps or clogged filters.
• Excessive bearing clearance: Worn crankshaft bearings or connecting rod bearings.

Quick diagnosis:

• Check the engine oil level and for leaks. Refill or replace the engine oil if necessary.
• Check the oil pump and filter. Replace them if necessary.
• Check the clearances of the crankshaft bearings and connecting rod bearings. Replace them if necessary.

8. High fuel consumption

Possible causes:

• Fuel system leaks: Loose fuel pipes or joints.
• Poor injector atomization: Worn or blocked injectors.
• Overload: The engine is operating under excessive load for a long time.

Quick diagnosis:

• Check the fuel system for leaks. Tighten or replace the fuel pipes if necessary.
• Check whether the injectors are worn or blocked. Clean or replace them if necessary.
• Reduce the load to avoid long – term overloading of the engine.

9. Excessive engine vibration

Possible causes:

• Loose engine installation: Loose fixing bolts or damaged bases.
• Unbalanced crankshaft: Worn crankshafts or detached counterweights.
• Uneven fuel injection: Poor injector atomization or inconsistent injection pressure.

Quick diagnosis:

• Check the engine fixing bolts and base. Tighten or replace them if necessary.
• Check whether the crankshaft is worn or the counterweights are detached. Replace them if necessary.
• Check the injectors and fuel pump to ensure uniform fuel injection.

10. High exhaust temperature

Possible causes:

• Late fuel injection: Incorrect injection timing.
• Insufficient air intake: Blocked air filters or air leaks in the intake pipes.
• Exhaust system blockage: Excessive carbon deposits in the muffler or exhaust pipe.

Quick diagnosis:

• Adjust the injection timing to ensure accurate fuel injection.
• Clean the air filter and check for air leaks in the intake pipes.
• Clean the muffler and exhaust pipe to ensure smooth exhaust.

The common malfunctions of single-cylinder air-cooled diesel engines are often caused by multiple factors. Regular maintenance and proper operation are the keys to avoiding malfunctions. SR POWER recommends that users follow the operation manual for maintenance strictly and regularly check the fuel system, lubrication system, and cooling system. In case of complex malfunctions, please contact professional technicians or the SR POWER after – sales service team in a timely manner. We will provide you with efficient and reliable solutions.