How to Winterize and Store a Suzuki Outboard: The Owner's Manual Procedure

Suzuki's storage procedure is short and nearly identical across the range: change the gear oil and the engine oil, add fuel stabilizer to the tank, flush the cooling passages with the engine running, run it at about 1500 r/min in neutral for five minutes to pull the stabilized fuel through (about 2500 r/min on the DF2.5), stop, grease the specified points and spray the powerhead with a rust preventative, wash and wax, then store it upright somewhere dry at a steady temperature. If the motor will sit for a month or longer, take the battery out.

That is the whole list. The Suzuki owner's manuals we work from do not include fogging oil, a carburetor drain or a cylinder treatment as storage steps; the stabilized fuel run and the rust-preventative spray are what Suzuki specifies. The steps below are the manual's, in the manual's order, with the family differences in a table.

Why the procedure looks the way it does

Each step answers a specific problem the manual names. Gasoline kept in the fuel tank for long periods of time will produce varnish and gum, which can damage the engine, so the fuel gets stabilized and the stabilized fuel gets run through the injection or carburetor system rather than left sitting in the tank. Salt is the second problem: after operation in muddy, brackish or salt water you flush the water passages, and if you do not, salt can corrode the motor and shorten its life. Storing at a constant temperature is to avoid corrosion caused by condensation. The oil changes come first because they are also an inspection: if the gear oil has a milky color, it is contaminated with water, and the manual says to contact your dealer immediately and not to operate the outboard until the oil is changed and the cause is corrected.

The storage procedure, step by step

1. Change the gear oil. Capacities and the fill-from-the-bottom method are on our gear oil capacity chart. Milky oil means water; stop there and see a dealer.
2. Change the engine oil. Quantities by model are on the oil capacity chart.
3. Fill a high quality fuel stabilizer to the fuel tank according to the instructions on the stabilizer can.
4. Flush the water passages thoroughly with the engine running: flushing muffs on the intake, or the motor in a drum of fresh water on the DF2.5 and DF4A/6A. Our flushing guide has the method by model. Never start it dry: severe engine damage can occur in as little as 15 seconds if the engine is started without supplying water to the cooling system.
5. Readjust the water flow and run the engine at about 1500 r/min in neutral for five minutes to distribute the stabilized fuel through the engine. The DF2.5 manual says about 2500 r/min for the same five minutes. On the DF75/90A, and on the DF150A/175A/200A in its 2023–2024 manual, the manual has you do this on the water before the flush.
6. Stop the engine, then turn off the water and remove the flushing attachment. On the DF2.5 and DF4A/6A, turn the fuel cock lever to the right (off). On a DF6A running a separate tank, disconnect the separate tank's fuel line from the fuel connector on the engine side (if provided) and install the fuel connector cap.
7. Lubricate all specified parts and spray the entire powerhead with a rust preventative (not a penetrating oil product). Before applying grease through the swivel bracket grease nipple (the steering bracket nipple on the DF4A/6A), lock the motor in the fully tilted up position.
8. Wash the exterior with fresh water and wipe it dry. A high pressure washer should be used only for washing the exterior, with the nozzle well away from the engine. (This step appears in the 2020 DF9.9B/15A/20A manual and later editions; the 2014 edition does not list it.)
9. Apply a coat of automotive wax on the external finish. If paint damage is evident, apply touch up paint before waxing.
10. Store the motor in an upright position in a dry, well-ventilated area. Select an area with constant temperature; do not store next to furnaces, heaters and the like.

Family differences

Battery

When the outboard motor will not be used for a month or longer, remove the battery and store it in a cool, dark place. Do not set the battery on concrete or earth, as this will accelerate loss of charge. Fully charge it, and if it will be stored for a long period, check the specific gravity of the fluid at least once a month and recharge the battery when the charge is low. When the season starts, the battery should go back on the motor fully charged; if it is time for a new one, our battery requirements chart has the minimum ratings by model.

Storing position and freezing weather

Upright is the only storage position the manuals give. Freezing weather adds a rule of its own: when the outboard is in the water in freezing temperatures, keep the lower unit submerged at all times, and when the motor is out of the water in freezing temperatures, stand it up in the vertical position so that the cooling system drains completely. Water left in the block can freeze and crack it; standing the motor upright is how Suzuki drains it.

If you have to lay a portable motor down to get it home, do it the manual's way. The DF9.9B/15A/20A manual's horizontal-transport steps start with draining the gasoline from the engine fuel line, then resting the motor on a case protector with the port side downward. The DF2.5 label is blunter: fuel can leak and create a fire hazard if you tilt the motor with a loosened air vent screw or lay the motor on its side. The vent screw should be closed for transportation and open for operation and cap removal.

Bringing it back in spring

The manual's after-storage list is short:

1. Thoroughly clean the spark plugs. Replace them if necessary.
2. Check the gear-case oil level and, if necessary, add gear oil according to the procedure in the gear oil section.
3. Lubricate all moving parts according to the lubrication section.
4. Check the engine oil level.
5. Clean the motor and wax the painted surfaces.

Add two checks of your own before the first trip. Look at the anodes: Suzuki says to inspect each of them periodically and replace them when 2/3 of the metal has corroded away, and never to paint them; our anode guide covers which ones your motor has. Then, on the first start, watch the pilot water hole: as soon as the engine starts, water should spray out of it, indicating that the water pump and cooling system are working properly. If it does not, stop the engine as soon as possible.

Parts for this job

A Suzuki oil change kit for your model, ECSTAR gear oil, Suzuki fuel conditioner and water remover for the stabilizer step, and a set of flush muffs cover the whole procedure; anodes, spark plugs and grease are in our Suzuki maintenance collections. Boat Max Online is an authorized Suzuki, Honda and Yamaha dealer; orders over $149 ship free to the lower 48.

Sources: Suzuki owner's manuals for DF2.5, DF4A/6A, DF8A/9.9A, DF9.9B/15A/20A (2014 and 2020), DF25A/30A, DF40A/50A/60A, DF75/90A, DF100A/115A/140A (2016, 99011-90J70-03B), DF115BG/140BG (2022–2023, 99011-99L20-03B), DF150A/175A/200A (2020; 2023–2024, 99011-96LM0-03B), DF150AP/175AP/200AP, DF225/250, DF250AP/300AP and DF300B/350A (2023, 99011-98L60-03B). Figures are Suzuki's published values; confirm against the manual for your model year and serial number.