Household and professional chainsaws are completed with simple in construction and reliable in operation two-stroke internal combustion engines. Much of the drive failures are due to malfunctioning of the fuel system. Why do you light a candle on a chainsaw and how do you fix this problem yourself?
Completing the entire sawmill range, the power units operate on a precisely metered mixture of fuel and special engine oil intended for the operation of two-stroke engines.
In the carburetor, fuel and air are mixed in a ratio of 1:16, after which the air-gasoline emulsion is fed into the combustion chamber.
Consequences of an engine running with unconfigured fuel equipment.
Traction characteristics of the engine and the duration of its resource depend on the composition of the mixture.
- Work on a poor mixture initiates a drop in power, overheating of the cylinder and intense wear of loaded parts and chainsaw assemblies.
- No less dangerous work on a rich mixture. The fault is manifested by an increase in the operating time, increased fuel consumption, smoke from the muffler.
- There is also an intensive formation of soot in the combustion chamber, loss of mobility of the piston rings.
Algorithm for determining the causes of poor mixing.
In any case, a wet candle on a chainsaw indicates a pronounced disproportion in the composition of the fuel-air emulsion. Already when the ratio of fuel and air is 1:14, the conditions of sparking deteriorate, the lack of air prevents the normal combustion of the air-fuel emulsion compressed in the combustion chamber.
The main reasons for re-enrichment of the mixture in most cases are standard:
- clogged air intake filter;
- improper carburetor adjustment;
- interruptions in the operation of the ignition system;
- poor quality of gasoline and violation of the power unit start-up sequence are also not excluded.
Risks of using low-quality fuel.
As part of various low-octane gasolines and fuel surrogates, there are alcohol components, which require more time for complete combustion. The economics of using such fuel is questionable, since there are a number of factors confirming inefficient operation and forced engine wear.
Candle fouling is facilitated by the use of heat-resistant motor oils for 4-stroke engines, high wear of compression rings or the entire piston group as a whole.
Troubleshooting Tips:
In the first case, the problem is solved by bringing the air intake device in good condition. A paper filter that has developed a resource is recommended to be blown out with a backflow of air, at best replaced. Methods for cleaning other types of filters are listed in the accompanying manuals.
- Adjustment of the carburetor is made on the engine warmed to the operating temperature. The power unit is brought to the optimum mode by rotating the adjusting screws for the quantity and quality of the mixture. The success of the work is determined by the knowledge of the design of the fuel supply system, the interaction of all components.
- In particular, the increased complexity of adjusting carburetors with built-in compensators and other elements of automatic control. Such equipment is configured using special equipment, which are equipped with service and repair centers.
If the engine cannot be adjusted, the cause of the excess fuel in the emulsion may be a valve leak or a carburetor float itself.
The final result of the work performed:
- quick turnaround;
- stable operation at idle;
- recovery of traction parameters;
- lack of increased smoke and detonation noise.
Criteria for the selection and operation of spark plugs:
The simplest mixture quality indicator is the porcelain insulator of the central electrode of the spark plug. Any shade of brown indicates a normal mix quality, a white or smoked insulator indicates poor or over-rich emulsion composition.
The heat of the spark plug must meet the stated requirements.
- The cause of oiling can be the so-called “cold” candle, which can be visually identified by a short insulator. Interruptions in sparking are possible if the gap is incorrectly adjusted or due to the natural burning of the contacts.
- The recommended distance between the contacts of the spark plug is indicated in the instructions; in the absence of information, one can be guided by the standard value of 0.7-1 mm. With a smaller gap, the efficiency of the ignition of the air-fuel emulsion is reduced, with an increased gap, sparking in sparking is possible.
- Burning a damp or oily candle on an open flame is not recommended because of the risk of cracking and premature failure.
Re-enrichment of the mixture in the combustion chamber of a technically sound chain saw is eliminated by blowing the engine. To do this, simply remove the candle and turn the crankshaft several times with a manual starter.