Preservation of a four-stroke outboard motor for the winter: a complete guide with a checklist

Why is the preservation of the engine not just a recommendation, but a necessity?

Winter is easy for four-stroke outboard motor Without proper preparation, even the most reliable unit from the Yamaha, Mercury or Honda It can become a headache by spring: oxidized contacts, thickened oil in the crankcase, corrosion on the piston group. four-stroke They need a holistic approach, and everything from the quality of the oil to the humidity in the storage room is important.

Many owners think that it's enough to drain the gas and put the engine in the garage. 70% of breakdowns after winter are associated with improper preservation. Inside the engine, there are microscopic droplets of water (even if you haven't been in the rain) that expand when you freeze and damage the metal. And the oil film on the parts loses its protective properties over time, allowing access to corrosion. Next, we'll look at how to avoid these problems step by step, taking into account the nuances for electronic injection motors.EFI) and carburetor models.

Step 1: Preparing the engine for conservation – what to do before draining the oil

Start with engine-washing This stage is often missed, but it is critical for removing salt deposits (if you have been swimming in sea water) and dirt from the cooling system. Mercury Quickleen or Yamaha Ring Free - they dissolve the deposits and deposits without the risk of damaging the seals.

The washing process:

• 🔹 Connect the motor to the water source (use an "ears" or special adapter).
• 🔹 Start the engine at idle speeds (not higher than the 1000 rpm).
• 🔹 Pour the flushing liquid into the fuel tank (dosage indicated on the package).
• 🔹 Let me work for 10-15 minutes, then shut down and let me cool.

After washing, be sure to check. condition If it's worn more than 50 percent, replace it -- it's a cheap part that will save expensive parts of the motor from electrochemical corrosion. Suzuki DF9.9–DF300 The anode is located on the bottom of the lower unit, Mercury 40-115 hp - under the anti-cavitation stove.

Step 2: Replacing oil and filters – nuances for four-stroke engines

The oil in a four-stroke engine is not just lubricant, but also a grease. barrier Old oil contains combustion products, acids and moisture, which in the winter will turn into an abrasive paste. hot-engine - so it leaks out as completely as possible. Honda BF50–BF250) use a vacuum pump.

Choice of oil for preservation:

Motor type	Recommended oil	Viscosity (SAE)	Replacement volume
Carburetor (up to 50 hp)	Mercury Premium four-stroke, Yamalube 4M	10W-30	0.8-1.2 l
Injection (50-150 hp)	Honda Marine four-stroke, Suzuki Marine Oil	10W-40	1.5–2.5 l
High-performance (over 150 hp)	Mercury Synthetic Blend, Valvoline four-stroke Marine	20W-50	3-4 l

Replace the oil after the drain. oil-filterThe filter accumulates up to 200 ml of old oil with impurities — if you don't change it, all the dirt will get into the new lubricant. Yamaha F25–F150 filter Yamaha 6E5-13440-00-00for Mercury 60-115 hp — Mercury 8M0139468.

Drain old oil on a hot engine |

Replace the oil filter|

Wash the crankcase (with severe pollution)|

Pour the new oil to the "FULL" mark on the probe |

Check the tightness of the drain plug--

Step 3: Fuel System – How to Avoid Clogs and Corrosion

Gasoline is the main enemy of the engine during storage, and when oxidized, it forms resins that clog. nozzle iv EFIThere are two options for preparing the fuel system:

1. Pour the gasoline completely It's suitable for carburetor engines, disconnect the fuel hose and let the engine run on idles until it dies, then blow the system with compressed air.
2. Add a fuel stabilizer - optimal for injection engines. Star Tron Enzyme Fuel Treatment or Mercury Quickstor Start the engine and let it work for 10 minutes so that the stabilizer spreads out over the system.

For engines with EFI (for example, Suzuki DF140–DF300) after adding the stabilizer, perform the procedure "Storage Mode" It'll shut down the nozzles and prevent the fuel from evaporating. Yamaha F150–F300 Similar mode is activated by holding the button SET within 5 seconds.

Step 4: Corrosion Protection – Treatment of internal and external surfaces

Corrosion starts where the moisture stays: in the cylinders, on the pistons, in the exhaust system. conservatory (for example, Fogging Oil from Mercury or Yamaha Storage SealProcessing algorithm:

1. Remove the spark plugs.
2. Pour into each cylinder 20-30 ml of oil through candle holes.
3. Scroll the crankshaft manually (or with a candle-free starter) 3-4 times to make the oil spread out.
4. Install the candles back, but do not tighten them completely - this will prevent the carving from deforming.

For external processing, use WD-40 Specialist Corrosion Inhibitor or CRC Marine GreaseApply the product to:

• 🔧 Reductor and lower unit (especially for engines with aluminum body).
• 🔧 Gas/reverse cable and a tiller.
• 🔧 Electrical contacts (battery, sensors, control unit).

What happens if you don’t use oil on the cylinders?

Without protective film, the cylinder walls will become microcorrosive during the winter, and in the spring, the piston rings will rip off the rust when they first start, leading to bullying on the cylinder mirror and loss of compression, and in advanced cases, you will need to plough the block or replace the cartridges.

Step 5: Preparation of the cooling system and gearbox

The water in the cooling system is a time bomb, and when it freezes, it expands and can break the pipes or damage them. water-pumpTo avoid this,

1. Pour water through the drain plugs (y) Mercury They are located on the cylinder block and exhaust system.
2. Blow the system with compressed air (pressure is not higher) 2 bar).
3. Pour antifreeze based on propylene glycol (for example, Sierra Marine Antifreeze) in a 50/50 ratio with water.

The gearbox needs special attention. Yamaha F25–F150 You have to unscrew two plugs, the drain plug and the control plug, and check the oil for metal chips, and if you have one, the gearbox needs to be diagnosed.Mercury High Performance Gear Lube motor-size 1.83:1 by the transfer number, Yamaha Gear Oil for 2.00:1).

Step 6: Storage of the motor – conditions that will prolong its life

Ideal storage conditions:

• 🌡️ Temperature: +5°C to +15°C (Avoid sub-zero temperatures and overheating).
• 💧 Humidity: not higher than 60% (use moisture absorbers, for example, Silica Gel).
• 🚫 It is forbidden to store the motor on the ground (use a pallet or shelf).
• ☀️ Lighting: no direct sunlight (UV destroys plastic and rubber).

The position of the motor during storage depends on the type:

• 🛥️ outboard motors (for example, Tohatsu MFS25): store in a vertical position (nose upwards) at an angle 45° for condensate drain.
• 🔧 Stationary motors (for example, Volvo Penta D3): leave in a horizontal position but tilted 5° towards the drain holes.

If the motor is stored in an unheated room, scroll the crankshaft every 2 months for 2-3 turns to avoid piston rings. hydraulic-tiller (for example, Mercury SeaPro) once a month, move the gas/reverse handle to the extreme positions, this will prevent the cables from souring.

Frequent errors and their consequences

Even experienced water-engineers sometimes miss important details, and here are the most common mistakes and what they lead to:

⚠️ Attention: If you didn't replace the oil in the gearbox, but just add the new, the old chips and the water will stay inside, and this will cause accelerated wear on the gears and bearings, and the repair costs 30 to 50 percent of the cost of the engine.

Other critical misses:

• 🚫 Use of automotive oil → sludge formation and clogging of oil channels.
• 🚫 Storage of the motor in a polyethylene case → The condensate does not evaporate, corrosion accelerates.
• 🚫 Forgot to take off the battery. → sulphation of plates, loss of capacity by 40-60%.

It is dangerous to ignore cylinderwork motor-wise direct-injection (for example, Evinrude E-TECThey do not flush the oil from the walls, so without conservation lubrication, the risk of bullies increases 3 times.

FAQ: Answers to frequent questions

Should I use a new engine before the first winter?

Yes, even if the engine only lasted one season, the metal shavings get into the oil during the break-in, and the fuel system accumulates deposits, skipping the canning will void the warranty from most manufacturers (for example, the scaling system). Honda Marine and Suzuki).

Can diesel oil be used to preserve a gasoline engine?

No, diesel oil has a different additive package and can damage the catalyst (if any) or rubber seals. NMMA FC-WBut they're hard to find at retail.

How to preserve the engine if there is no possibility to drain gasoline?

Add it to the fuel tank. stabilizer Double dose (1:50) and let the engine run for 15 to 20 minutes on idle, then turn off the fuel hose and wait until the engine dies from lack of gasoline, which is better than leaving the fuel untreated.

What if the engine was stored in winter without preservation?

Don't panic. Before launch:

1. Pour the old oil and pour the washing (for example, Liqui Moly Motor Clean).
2. Scroll the crankshaft manually - if you feel resistance, do not start the engine (disassembly will be required).
3. Check the compression in cylinders (norm: at least) 10 bars in each).
4. Replace the candles and fuel filter.

If the engine does not start or is working intermittently, contact the service - you may need to clean the nozzles or replace the piston rings.

Can I keep my motor on a boat in winter?

You can, but only if the boat is in the heated-barrel It's humidity control.

• Remove the motor from the transom and store it on the stand.
• Cover the engine. breathable (e.g. from Sunbrella).
• Check every 2 weeks for no condensation under the cover.

Storage in an open area or in unheated box is unacceptable - it is guaranteed corrosion of lower unit and electronics.