Three winter risks
- Frost: water left in cooling passages and hoses can freeze and burst them.
- Corrosion: salt and moisture attack the metal from the inside.
- Stale fuel: petrol breaks down and leaves deposits in the carburettor and fuel lines.
1. Flush with fresh water
Flush the engine with fresh water after the last trip of the season – whether it has run in salt, brackish or fresh water. Attach flushing muffs or lower the engine into a flushing tank and let it run. At the same time, check that the cooling water tell-tale stream is strong and steady.
Flushing is also a good opportunity to listen for unusual noises.
2. The fuel
- Add fuel stabilizer and run the engine so the stabilized fuel reaches the carburetor or injection system.
- Alkylate petrol keeps better than regular petrol, but it also benefits from stabilizer during long storage.
- Some manufacturers instead say the carburetor should be run dry. Always follow the engine manufacturer's owner's manual.
3. Oil and lubrication
- Four-strokes: change the engine oil and filter before winter so the contaminated oil doesn't sit in the engine.
- Change the gear oil. Milky oil means water in the gearcase.
- Lubricate according to the lubrication schedule and spray fogging oil into the cylinders if the manual says so.
4. Store upright and look after the battery
Store the outboard upright in its normal running position with the lower unit pointing down. That way any remaining water drains out of the cooling passages instead of collecting where it can freeze. Don't lay the engine down on the wrong side – oil can run where it shouldn't.
If you take the engine home, a sturdy engine stand in a frost-free space is best.
Fully charge the battery and check the charge during storage according to the battery manufacturer's instructions.
Checklist to tick off
- Flushed with fresh water and the cooling water tell-tale checked.
- Stabiliser in the tank, or carburettor drained according to the manual.
- Engine oil and filter changed (four-stroke).
- Gearcase oil changed and checked for water.
- Greased according to the lubrication schedule.
- Propeller removed, shaft checked for fishing line and greased.
- Stored upright, frost-free and dry.
- Battery charged and disconnected.
- Note on the engine of what has been done.
Old two-stroke?
Older two-stroke engines with carburettors release 20–30% of their fuel unburned into the water. An engine like this can be handed in for scrapping free of charge. If you're replacing it, ask for a quote on a new engine or on servicing the old one.
Frequently asked questions
Should an outboard be stored upright or lying down?
Upright in the normal running position with the drive down, so the water drains from the cooling passages.
Do I have to flush the engine if I've run it in fresh water?
Yes, it's recommended. Even fresh water carries sand and particles that should be flushed out before the engine is laid up.
Should I drain the carburetor or add stabilizer?
It varies between manufacturers and models. Follow the manual for your engine.
How often should I check the battery in winter?
Check the charge during storage according to the battery manufacturer's instructions.
Sources
- Vinterkonservering av din båtmotor, Biltema biltema.se
- Båtmotorer och utsläpp, Transportstyrelsen transportstyrelsen.se
- Motorvård för båtmotorer, Biltema biltema.se