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| Home / Car Engines / Nissan Engines / Nissan A12A |
Nissan A12A Troubleshooting
| Engine difficult to start or doesn't start |
Empty fuel tank - Add fuel.
Wrong fuel grade - Use quality gasoline.
Air in fuel tank - Bleed fuel tank.
Damaged spark plug wiring connection - Inspect the spark plug wire connection, replace or repair.
Faulty spark plug - Spark plug need to be replaced.
Defective ignition - Test ignition and replace failed parts.
Dirty fuel filter - Replace fuel filter.
Clogged fuel lines - Service fuel lines.
Clogged or damaged fuel pump - Check fuel pump and replace if necessary.
Carburetor malfunction - Check and repair as required.
Engine has low compression - Check cylinder block and replace defective parts.
| Irregular engine running |
Ignition system malfunction - Inspect ignition system and change failed components.
Plugged air filter - Clean or replace.
Spark plug is damaged - Spark plug need to be replaced.
Dirty or defective fuel pump - Clean or install new fuel pump.
Incorrect valve clearance - Adjust to proper valve clearance.
Wrong ignition timing - Set the ignition timing properly.
Wrong adjustment of low idle speed - Correct idle settings.
| Engine stalls after starting |
Damaged spark plug - Spark plug need to be replaced.
Clogged or defective carburetor - Service or repair carburetor.
Ignition coil is defective - Ignition coil must be replaced.
Broken or bad valve springs - Install new valve springs.
Valves are stuck - Service the valves.
| Engine overheats |
Lack of engine oil - Check oil level and add oil as required.
Engine overloaded - Reduce engine load.
Too lean fuel mixture in carburetor - Set the carburetor correctly.
Incorrect ignition timing - Ignition timing needs to be set properly.
Valve setting is incorrect - Valves needs to be set correctly.
Dirty radiator fins or defective radiator cap - Change cap or clean radiator.
Low engine coolant - Add coolant fluid and inspect the cooling system for leaks.
Thermostat is defective - Change thermostat as required.
Water pump is defective - Change water pump as required.
| Engine knocking sound or abnormal noise |
Low octane gasoline - Use proper gasoline.
Engine is running overloaded - Load reducing required.
Insufficient engine oil - Fill up the oil to required level.
Low idle speed setting is incorrect - Correct the settings.
Fuel pump is faulty or clogged - Check fuel pump and replace if necessary.
Main bearings or crankshaft wear - Have bearings or crankshaft replaced.
Valve clearance is wrong - Adjust valve clearance according to specifications.
Damaged piston rings or cylinder bore - Change faulty parts.
| Engine loses power |
Dirty or incorrectly adjusted carburetor - Carburetor needs to be adjusted correctly or cleaned.
Air filter element is clogged - Clean or replace air filter.
Clogged or defective fuel pump - Check fuel pump and replace if necessary.
Defective ignition - Test ignition and replace failed parts.
Defective cylinder head gasket - Replace cylinder head gasket.
Burned or stuck valves - Replace or service valves.
Faulty cylinder block parts - Replace defective components.
Plugged oil filter - Change or clean oil filter.
| Engine uses too much fuel |
Air filter element is clogged - Change or service air filter.
Carburetor main jet adjustment is incorrect - Adjust it correctly.
Spark plug is loose or defective - Re-tighten or change the spark plug.
Wrong ignition timing - Ignition timing needs to be set properly.
Valves are worn, burned or stuck - Change or service valves.
Worn sleeve, piston, or rings - Replace defective components.
Valve clearance is incorrect - Adjust valve clearance according to specifications.
Poor engine compression - Check cylinder block and replace damaged components.
| Excessive engine oil consumption |
Worn seals or gaskets - Worn parts need to be replaced.
Valve stems and guides are worn - Replace defective valves.
Piston rings are defective or worn - Change piston rings.
Damaged piston or cylinder liner - Check liner and piston, replace as required.
| Engine backfires |
Too lean fuel mixture in carburetor - Set the carburetor correctly.
Fuel lines are clogged - Fuel lines need to be cleaned.
Incorrect ignition timing - Ignition timing needs to be set properly.
Wrong valve setting - Adjust valves correctly.
Air filter element is clogged - Clean or change air filter.
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