Carbon in engine cylinders: how to recognize, remove and prevent

Engine cylinders are one of the most common problems faced by outboard and car owners, and this black or brown coating not only reduces engine efficiency, but can also cause serious breakdowns if not addressed in time. Where does the load come from, how do we detect it, and what can be done to restore the normal operation of the motor? In this article, we will look at all the nuances, from the causes of education to the methods of cleaning and prevention.

Many people mistakenly think that nagar is just a problem with old engines, and actually it's even produced in new engines when operating conditions are broken or when consumables are poor, and this is especially true for outboard motorists, where load surges and erratic revs create ideal conditions for deposits, and let's figure out how to recognize the problem early and what to do to make the engine last longer.

Let me just say that it's not a sentence, and if you do it right, it can be removed, and it can be prevented, and the key is not to ignore the first signs, and not to make it critical when you need to overhaul.

What is stainless and how is it formed in cylinders

Nagar is a solid carbon deposit that forms on the walls of the combustion chamber, pistons, valves and spark plugs, and is made up of unburned particles of fuel, oil and additives that are sintered under high temperatures. In outboard motors, which often use two-stroke engines with oil in fuel, the coar is formed especially intensively.

The process of formation of sodium can be divided into several stages:

1. Incomplete combustion of fuel - due to improper fuel air mixture, poor quality gasoline or poor compression.
2. Getting oil into the combustion chamber - through worn oil removable rings, valve oils or when oil is poured into the crankcase.
3. High-temperature sintering - with engine overheating or prolonged work at high revs, the deposits are compacted and turn into a solid raid.

In two-stroke outboard motors (for example, Yamaha 15LMHS or Mercury 9.9) The carbon is produced more quickly because of the design: the oil burns with the fuel, and the lubrication system is less perfect than in four-stroke engines. Honda BF50 or Suzuki DF60) the problem is more often associated with wear of the rings or valves.

Interesting fact: the color of the coar can tell a lot about the state of the engine. Black velvety garnet Usually indicates a rich fuel mixture, white-grey - to get oil, and reddish - the presence of additives in fuel (for example, ferrocenes in cheap gasoline).

Causes of the formation of sodium: from fuel to operating modes

Nagar doesn't appear by itself -- it's always preceded by specific malfunctions or errors in operation. Let's look at the main causes, starting with the most common ones:

1. Low quality fuel or oil

• 🛢️ Cheap gasoline high content of sulfur or additives (for example, AI-92 substitute AI-95) does not completely burn, leaving soot.
• 🧴 The wrong oil for two-stroke engines (e.g., using automotive oil instead of specialized oil) 2T).
• 🔥 Ferrocene additives In fuel (often found in uncertified gasoline) during combustion form a hard reddish coating.

Violation of the proportions of the fuel mixture

• ⚖️ Too rich a mixture (excess gasoline) is a classic problem of carburetor engines, for example, Tohatsu 18 or Parsun 9.8.
• 💧 Oil transfusion in two-strokes (exceeding the norm of 1:50 or 1:100) leads to its combustion and the formation of lacquer deposits.

Failures in the ignition and fuel supply system

• ⚡ A faint spark. on candles (due to wear or improper gap) leads to incomplete combustion of the mixture.
• 🔧 Clogged nozzles (in injection engines) or chiclers (in carburetor) violate the spray of fuel.
• 🌡️ Misfunction of sensors (e.g., a lambda probe or temperature sensor) knocks down the composition of the mixture.

4. Operational factors

• 🚤 Long-term idle work (for example, with trolling) contributes to the formation of sodium due to the low combustion temperature.
• 🔥 Overheating of the engine (due to clogged waterways or faulty thermostat) accelerates sediment sintering.
• 🛑 Sharp loads (for example, a sharp opening of the throttle after a long work at low speeds) provoke detonation and increased nagaroformation.

Signs of sodium in cylinders: how to recognize the problem

Cylinder engarment rarely appears suddenly, usually preceded by indirect signs that can be seen long before serious consequences.

Changes in engine operation

• 🔊 Detonation knocks (metal ringing during acceleration) - a sign that the scoop disrupts the normal combustion of the mixture.
• 🐢 Loss of power and "dumbness" of the engine when set to speed (especially noticeable in outboard motors when entering the planing).
• 🌀 Uneven idling or spontaneous change of revolutions (for example, the motor "trips").

2. Launch problems

• 🔥 Difficult hot-start. - Scores on candles or valves worsen spark formation.
• ❄️ Starting "cold" from half-turnBut then the motor stops -- a sign of the rings coming from the swelling.

3. Visual and other signs

• 🔍 Black smoke from the exhaust pipe (in outboard motors - from water jet nozzle) - evidence of incomplete combustion of fuel.
• 💡 Lighting plugs in black raid (If they are covered with soot after 100-200 km or 5-10 hours of motorized driving, this is an alarming signal).
• 🛢️ Increased oil consumption (in four-stroke engines) or fuel (in two-stroke) due to deterioration of compression.

A critical sign requiring immediate intervention: metal shavings in oil or on the pallet's magnetic plug, suggesting that the coar has already caused mechanical wear on parts (such as rings or cartridges).

You can use a simple test to diagnose this: turn the spark plug and examine its electrodes. If they're covered in dry black coating (like soot), it's a sign of the rich mixture's soot, and if the coating is oily, the problem is getting the oil into the combustion chamber.

How to check compression without a compressometer?

If there is no compressometer at hand, you can roughly assess the compression "by eye":

1. Turn all the candles out.

2. Scroll the engine with a starter, covering the candle hole with your finger.

3 In a serviceable cylinder you should feel strong air resistance (the finger will literally "suck" to the hole).

4 If there is almost no resistance, the compression is critically low, possibly due to the swelling on the rings or valves.

Note: This method does not give exact figures, but it will help to identify obvious problems.

The consequences of soda: why you can not ignore the problem

Many motorists and motorists spend years in the cylinders without knowing the damage it causes to the engine, but the consequences can be very serious, even to the point of complete failure of the engine.

Mechanical damage

• 🔥 Positioning of piston rings - the soda fills the gaps between the piston rings and grooves, depriving them of mobility, which leads to loss of compression and oil entering the combustion chamber.
• 🚪 Valve jamming - deposits on saddles and plates of valves prevent their complete closure, which leads to burnout.
• 💥 Detonation devastation - Pont increases the degree of compression, which when using low-octane fuel leads to microexplosion and damage to pistons.

Deterioration of heat sink

• 🌡️ Nagar acts as a thermal insulator: the cylinder head and pistons overheat, which accelerates wear and can lead to scorch.
• ⚡ In outboard motors, overheating is especially dangerous - it can cause deformation of cylinder casings (for example, in the case of a cartridge). Tohatsu MFS25 or Evinrude E-TEC).

3. Economic losses

• ⛽ Increased fuel consumption 10-30% due to the deterioration of the combustion of the mixture.
• 💰 Expensive repairs - the occurrence of rings or burnt valves will require disassembly of the engine and replacement of parts.

⚠️ Attention! In two-stroke outboard motors, nagar is especially dangerous for vent-window Their clogging causes power loss and can cause a hydraulic shock when water enters the exhaust system.

The table below shows how the scalp affects different types of engines:

Type of engine	Consequences of sofare	Risk of critical failure
Two-stroke outboard motor	Clogging of exhaust windows, loss of compression, overheating	High (water impact, jamming)
Four-stroke outboard motor	Rings, valve burn, oil starvation	Medium (requires major repairs)
petrol-powered	Detonation, power reduction, increased fuel consumption	Low/medium (with timely cleaning)
Diesel engine	Clogging of the particulate filter, reducing the efficiency of the turbine	High (if ignored)

How to remove stained steel: mechanical and chemical methods

If the stain is already formed, it needs to be removed, the cleaning methods depend on the degree of contamination and the type of engine, and let's look at the most effective methods, from preventive to heavy artillery.

Chemical cleaning (without disassembling the engine)

• 🧪 Fuel additives (for example, LIQUI MOLY Ventil Sauber or Wynn's Combustion Chamber Cleaner) - added to the gas tank and gradually dissolved the soda. Effective for weak deposits.
• 💊 "Discovery." - special compositions (e.g. LAVR ML202 or GZOX) which are filled into cylinders through candle holes, requires exposure of 1-12 hours and subsequent scrolling of the engine without load.
• 🛢️ Oil system flushing (for example, Hi-Gear HG2211) removes lacquer deposits in lubrication channels.

Mechanical cleaning (with partial disassembly)

• 🔧 Cleaning of the combustion chamber by hand - requires removal of the cylinder head (CBC) and removal of the scoring with a scraper or sandblaster.
• 🧹 Ultrasonic cleaning - parts (valves, pistons, nozzles) are placed in a bath with solution, where ultrasound destroys the loot, used in service centers.
• 🔥 Burning of sodium In some services, special burners are used for controlled burning of deposits (the method is risky and requires experience).

3. Radical methods (for critical pollution)

• 🔄 Replacement of piston rings If the stains caused them to wear and tear.
• 🛠️ Honing or cylinder swelling - with deep scratches from abrasive particles of locomotion.
• 🔧 Replacement of valves or saddles - if the scorching caused them to burn.

Remove spark plugs or incandescents

Blow the cylinders with compressed air (to remove dust)

Heat the engine to operating temperature (if indicated in the instructions for the tool)

Prepare a tool for scrolling the crankshaft (key or starter)

Have a new oil and filter on hand (after the procedure, they must be replaced).

For outboard motors (especially two-stroke ones), mechanical cleaning is often complicated by design, and in such cases, it is recommended to combine chemical decoking with fuel system washing.

⚠️ Attention! Mechanical cleaning of the scoop Do not use metal brushes or sandpaper. They leave scratches that will speed up the re-formation of sediments, and the best option is plastic scrapers or wooden sticks.

Prevention of sodium: how to prevent the formation of deposits

The best way to combat the problem is to prevent it from appearing, and you just have to follow a few simple rules that will prolong the life of your engine and save money on repairs.

1. Use quality fuel and oil

• ⛽ petrol - Refuel at the checked gas stations (for example, LUKOIL, Gazpromneft, RosneftAvoid gasoline with an octane number below the manufacturer's recommended value.
• 🧴 Oil For two-stroke outboard motors, use only specialized oils with labeling TC-W3 (for example, Quicksilver Premium two-stroke or Yamalube 2-M).
• 🔄 Proportions of mixture Strictly observe the ratio of oil / gasoline (usually 1:50 or 1:100, see the instructions for the engine).

2. Monitor the ignition and fuel supply system

• ⚡ Ignition plugs Change every 100 hours (or according to the regulations) and check the gap between the electrodes (for most outboard motors, the engine is not the same). 0.7-0.9 mm).
• 🔧 Air filter A clogged filter enriches the mixture, leading to soaking. Change or flush it every 50 hours.
• 💡 Carburetor/injector - once a season, clean and adjust the power system. Mercury 15) check the level of the float and the purity of the chicler.

Correct operating modes

• 🚤 Avoid long-term work on idle turns If the motor is to run at low speeds (for example, when trolling), periodically "gass" it.
• 🌡️ Control the temperature. Overheating speeds up the formation of sodium. Watch the cooling system (in outboard motors, the flow of water through the water). tell-tale).
• 🛑 Do not turn off the engine immediately after loading Let him work 1-2 minutes on singles to cool down (relevant for two-tacters).

Regular maintenance

• 📅 Routine diagnostics Once a season, check the compression, condition of candles and valves.
• 🔄 Oil replacement In four-stroke engines, change the oil every 50–100 hours (or according to the regulations).
• 🛠️ Fuel system cleanup Use injector or carburetor cleaners (for example, Sea Foam for outboard motors.

Frequent mistakes in dealing with smog

Many owners who have faced swelling make mistakes that only make the problem worse, and these are the most common ones -- and how to avoid them.

1. Use of “popular” cleaning means

• 🧂 Acetone, kerosene or diesel These solvents can damage engine seals and rubber parts. Use only certified compounds.
• 🍋 Citric acid or vinegar - useless against carbon deposits and can cause corrosion of the metal.

2. Wrong decoction

• ⏱️ Inadequate exposure If the instructions indicate to keep the composition for 12 hours, and you are limited to 1-2 hours, the effect will be minimal.
• 🔥 Scrolling the engine without draining oil - after decoking, the particles of soda enter the oil and clog the oil channels. Always change the oil and filter after the procedure.

3. Ignoring the root cause

• 🔍 Cleaning the scoop without eliminating the cause If you do not correct the rich mixture or leak oil, the soda will return in a few hundred kilometers.
• 🛠️ Self-repair without diagnosis For example, replacing the rings without checking the compression or condition of the cylinders.

4. Operational errors after cleaning

• 🚀 Load on the engine immediately after decoking - Let the engine work for 10-15 minutes on idle, so that the remnants of the product burn out.
• ⛽ Use of low-octane gasoline - after cleaning, it is especially important to refuel with high-quality fuel, so as not to provoke the re-formation of sodium.

⚠️ Attention! Never use it for decocting. soda or other abrasive powdersThey scratch the surface of the cylinders and pistons, which further accelerates wear and formation of new coar.

FAQ: Answers to Frequent Questions About Cylinders

Can I drive in cylinders if the engine is still running?

Technically possible, but highly undesirable. Nagar impairs heat sink, increases the risk of detonation and leads to accelerated wear of parts. If you ignore the problem, after 1-2 seasons, major repairs (replacement of rings, valves, cylinder ploughing) may be necessary. It is especially dangerous to drive with a load on outboard motors, because of the risk of hydraulic shock when the exhaust windows clog.

How often should I do the decoding?

This depends on the type of engine and operating conditions:

• For two-stroke - once in 1-2 seasons or every 100-150 motor hours.
• For four-stroke boat and motor motor engines - once in 50-80,000 km or when signs of coarseness appear (power loss, smoke).
• For arch-engine (with a run of > 150 thousand km) - once every 30-50,000 km for preventive purposes.

If you use high-quality fuel and oil, the interval can be increased.

What is the most effective means for cleaning?

The effectiveness depends on the degree of pollution:

• Light tan. - fuel additives (LIQUI MOLY Ventil Sauber, Wynn's Combustion Chamber Cleaner).
• Medium-sized garnish - liquids for decoking through candle holes (LAVR ML202, GZOX, Mitsubishi Shumma).
• Strong garlic - mechanical cleaning or ultrasonic bath (in the service).

For outboard motors it has proved itself well. Yamaha Ring Free It not only removes the stain, but also protects against corrosion.

Can I clean the stain without disassembling the engine?

Yes, in the early stages, it's possible with chemical agents, but if the scent has already caused rings to become deposited or valves to burn, you'll need to disassemble.

• The thickness of the deposits (up to 1-2 mm chemistry will cope, above - a mechanical method is needed).
• Engine type (two-stroke engines are cleaned worse due to design features).
• The quality of the product used (cheap additives are often useless).

After chemical cleaning, be sure to replace the oil and oil filter!

What if the engine started to work worse after the engine was decoding?

This is possible for several reasons:

• Wrong procedure For example, the product did not withstand enough time or did not drain the old oil.
• Leaching sediments from oil channels - the carbon particles could clog the oil receiver or the filter, so you need to change the oil again.
• Detecting Hidden Problems - decoking could "open" wear rings or valves, which was previously masked by soot.

If after decoking the engine triples, smokes or does not develop speeds, contact the service for the diagnosis of compression and valve condition.