"Shooting" in a muffler is not only an unpleasant phenomenon. This noise "effect" indicates a malfunction in the engine. Therefore, it is important to establish the cause of the malfunction in a timely manner in order to eliminate it as soon as possible.
Shots in the muffler can easily lead to rupture or damage to the resonator (s), which will result in material costs associated with buying a new part and installing a muffler on a car. Moreover, improper engine adjustments will “help” damage more expensive parts than a muffler and resonators. On gasoline engines, there are several reasons for the appearance of "shooting", which can begin as a result of a failure of one of the auto systems.
Power system (carburetor)
A very loud pop in the muffler indicates that fuel is burning in the exhaust system. This may be due to improper adjustment of the carburetor (mixture quality screw), as a result of which there is too much gasoline in the fuel mixture. This leads to the fact that the fuel does not burn completely in the cylinders (at the moment of the compression stroke) and "flies" straight into the muffler, where it ignites at high temperatures. Make sure the air filter is in good condition before making carburetor adjustments.
Gas distribution mechanism (timing)
If shots into the muffler are heard at all engine operating modes (low, medium, high revs), then it makes sense to check the thermal clearances in the valves. The valve seat very tightly closes the inlet (outlet) to the cylinders; when the gap is reduced, this cannot be done - a gap remains. As a result, the fuel mixture partially seeps into the exhaust manifold, where it ignites with a roar. You can get rid of pops by simply adjusting the valves - each car model has its own clearance. When making adjustments, do not forget that when heated, the metal expands, and the gap on a warm engine becomes smaller than on a cold one.
Ignition system
Ignition too late can also cause muffler popping. The reason is the illiterate adjustment of the ignition timing. If it is configured correctly, then a spark between the electrodes of the spark plug should appear at the moment when the piston overcomes top dead center (or TDC). The ignition of the mixture pushes the piston; when the ignition is delayed, a spark will appear when it has already gone down, the movement is accompanied by the opening of the exhaust valve. As a result, the mixture ignites and "slips" through the open valve into the exhaust manifold, where the cotton occurs.
