Won't the car catch fire in cold weather?

1. The combustible mixture is too strong. Unburned residue will accumulate on the spark plug electrode for carbonization, which will cause the spark plug to flash abnormally until it is damaged by carbonization. The reasons for the concentration of combustible mixture exceeding the standard are generally that the oil level of carburetor is too high, the main air hole of carburetor is blocked, and the filter element of air cleaner is seriously blocked. In addition, the choke valve of carburetor is stuck and cannot be fully opened, or the enrichment valve is not easy to use, which is also the reason why the concentration of combustible mixture exceeds the standard.

The engine is leaking oil. When the engine is working, if the exhaust pipe emits blue smoke and black smoke, it means that excessive engine oil enters the cylinder, which will cause a lot of carbon deposition on the spark plug electrode or be wet by engine oil, which is also commonly known as oil channeling. For two-stroke engines, it is necessary to check whether the oil pump pumps too much oil, and whether the rod sleeve seal and one-way valve fail. For a four-stroke engine, check whether the piston ring, especially the oil ring, is worn. Then remove the intake valve and check whether there is carbon deposit and wet grease on the head and back. If the valve and valve guide are seriously worn, the valve guide oil seal is hardened or the lip of the oil seal is excessively worn, the matching clearance is too large and the sealing effect is lost. These two abnormal conditions will eventually lead to the phenomenon that the oil in the rocker arm chamber of the valve is sucked into the cylinder along the valve stem when the intake air is summarized, resulting in the combustion of the oil. In this regard, the valve guide, oil seal or valve should be replaced according to its wear and tear.

3. In the ignition system, loss of excitation of magneto, loose connection between ignition coil and electronic igniter, generator output and ignition coil input, and incorrect ignition advance time will all affect the ignition performance, and poor ignition performance will directly cause carbon deposition on spark plug electrode.

4. Pay attention to whether the model and calorific value of the spark plug meet the requirements of the instruction manual. If the calorific value is one or two steps lower than the instruction manual, the temperature of the spark plug will rise very high, and its heat will not be dissipated in time, which will cause abnormal combustion and eventually lead to premature melting and damage of the spark plug electrode. When the spark plug itself is installed and used, there are still some faults that are not easy to be found, which also affect the ignition performance. For example, the spark plug is poorly sealed, the spark plug is not firmly fixed, and the insulator of the spark plug is damaged, so it should be adjusted or replaced in time. 5. If the crankcase oil is filled too much, if the breather pipe is blocked, the internal pressure of the crankcase will increase and be unbalanced.