Muffler blasting is the explosion of unburned combustible mixture when it is re-burned in the muffler, often accompanied by sparks, commonly known as blasting. Muffler shooting will lead to high engine working temperature, poor acceleration performance and weak driving. The reasons are usually as follows:

1. The mixture is too strong.

The combustible mixture of the engine is too rich to burn completely and is discharged with the exhaust gas. When it meets fresh air in the muffler, it burns again and explodes. When the engine is running at low speed, the sound is heavy and unstable. When the engine is running at high speed, the muffler shooting is obviously improved or even disappeared.

2. The oil level in the float chamber is too high.

If the oil level in the float chamber is too high, it will not only cause the combustible mixture to be too rich, but also make a part of the fuel directly enter the cylinder without sufficient atomization, and it will not be completely burned in the cylinder, and then it will be re-burned with the exhaust gas in the muffler, resulting in deflagration. If the muffler discharges a large number of oil beads, fuel still flows out after parking, indicating that the oil level in the float chamber is too high or the oil needle in the float chamber is not tightly sealed, and the carburetor should be cleaned or replaced.

3. The ignition advance angle is too small

The ignition is too late, which prolongs the combustion time of combustible mixture, and the unburned combustible mixture produces secondary combustion in the muffler, which leads to the muffler firing. At this time, the ignition time should be adjusted or the magneto should be replaced.

4. The spark plug is broken or unstable.

The combustible mixture in one stroke failed to ignite, but it was exhausted and ignited by the high temperature gas in the next stroke. This phenomenon is intermittent and irregular, the engine power drops obviously, and it is easy to stall when accelerating. At this time, the spark plug should be removed for flashover test. If the spark plug is damaged or unstable, remove the carbon deposit or replace it with a new one.

5. Too much oil is fed during startup.

The follow-up work caused by repeated start-up leads to excessive concentration of combustible mixture, which not only causes a large amount of fuel accumulation in the cylinder, but also discharges a large amount of oil beads from the muffler. After the engine is started, the fuel in the muffler burns, causing deflagration. This phenomenon will disappear by itself with the normal operation of the engine.

Second, the exhaust pipe emits black smoke.

Black smoke indicates that there are too many carbon particles in the exhaust gas, which is caused by incomplete combustion when the engine is running. The reasons are usually as follows:

(1) The combustible mixture is too rich.

(2) The mixing ratio of gasoline and engine oil in the mixed oil is incorrect, or the brand of engine oil used is wrong. When the engine oil is too much or the engine oil quality is poor, the engine oil in the combustible mixture can not be completely burned, resulting in black smoke.

(3) Two-stroke engines with separate lubrication have unbalanced oil pumps and excessive oil supply.

(4) The crankshaft oil seal of the two-stroke engine is damaged, and the oil in the gearbox enters the crankcase and enters the combustion chamber with the mixed gas, resulting in too much oil in the mixed gas.

(5) The oil ring in the piston ring of the four-stroke engine is seriously worn or broken, and the oil escapes into the combustion chamber.

(6) Four-stroke engine oil overload. A large amount of engine oil escapes to the upper part of the piston and enters the combustion chamber for combustion.

(7) The cylinder liner of the water-cooled engine is damaged, and the cooling water enters the cylinder, which affects the normal combustion. If it is found that the smoke emitted is slightly white and the water in the water tank is consumed too quickly, this is the reason.

The exhaust pipe emits black smoke, which is often accompanied by failures such as spark plug failure, oil consumption, difficult start-up and power drop. On the other hand, various faults are often interrelated. XDZl25 in Sundiro has the phenomenon of beating, and the fire is accelerating.

Fault phenomenon: a motorcycle of XDZl25 in Sundiro has slow speed increase, and the car catches fire when driving, and the fire breaks when accelerating. Fault analysis and elimination: According to the above phenomenon analysis, this fault may be caused by circuit or oil circuit. When overhauling, first remove the carburetor for inspection and cleaning. After inspection, no abnormality was found in the carburetor. After cleaning, the carburetor was reassembled for debugging, and the fault still existed. So check the circuit, remove the spark plug cap and do the flashover test. The spark is weak, and it is certain that the problem lies in the circuit. Disconnect the output end of the igniter and conduct grounding test. The spark is weak, indicating that the igniter is faulty. Replace the new igniter. Starting test shows that the engine starts smoothly and accelerates well, and the fault is eliminated.

After Jincheng JCl25 cleaned the carburetor, there was a spark phenomenon.

Fault phenomenon: When a Jincheng JCl25 motorcycle was tested after cleaning the carburetor, the exhaust pipe exploded and the engine could not operate normally.

Troubleshooting: There may be two reasons for the explosion of exhaust pipe:

(1) The mixing ratio is incorrect.

(2) There is something wrong with the ignition system.

During maintenance, carefully check the installation of carburetor according to the principle of moving where you are looking, and no abnormality is found. Check the spark plug for misfire, which is basically normal. Later, a new spark plug was used to test and troubleshoot. This shows that the spark plug of the original factory has a slight insulation breakdown phenomenon, which can not be ignited normally under the action of high temperature and high pressure gas in the combustion chamber, which makes the In gas not burn normally, thus leading to fire from the exhaust pipe.

Third, the ignition advance angle is too small

The ignition is too late, which prolongs the combustion time of combustible mixture, and the unburned combustible mixture produces secondary combustion in the muffler, which leads to the muffler firing. At this time, the ignition time should be adjusted or the magneto should be replaced. Ignition plug b failed to ignite the combustible mixture in a certain stroke when the fire was on or weak, and was ignited by the high temperature gas in the next stroke after it was exhausted. This phenomenon is intermittent and irregular, the engine power drops obviously, and it is easy to stall when accelerating. At this time, the spark plug should be removed for flashover test. If the spark plug is damaged or unstable, remove the carbon deposit or replace it with a new one.