How do I winterize an outboard motor?
Winterizing an outboard · Symptom: Preparing for storage / freezing temps.
Quick answer: Start here: Stabilize fuel and run in water so it circulates (Honda: ~10 min). If that doesn't fix it, work through the checks below, and see a marine mechanic if you're unsure.
Safe owner checks & fixes
- Stabilize fuel and run in water so it circulates (Honda: ~10 min).
- Flush cooling system with fresh water.
- Change engine oil (4-stroke) and gear lube; milky lube = water intrusion → dealer pressure test.
- Pull prop, remove fishing line from shaft, grease shaft.
- Fog cylinders per manual.
- Disconnect/charge battery.
- Store motor vertical/tilted down so water drains.
Parts / tools
Flush muffs, fogging oil, gear lube pump & lube, oil/filter, stabilizer, grease, prop wrench.
Call a marine mechanic when
Gear lube is milky (pressure test); you can't fog or drain per manual; 4-strokes with exposed timing belts if unsure; any leaks found. If you're on the water and unsafe, call TowBoatUS/Sea Tow or the Coast Guard (VHF 16).
Sources
- https://www.mercurymarine.com/us/en/lifestyle/dockline/how-to-winterize-your-outboard
- https://dwr.virginia.gov/blog/15-tips-for-winterizing-your-boat-and-motor/
- https://cdn.powerequipment.honda.com/marine/pdf/maintenance/Avoiding-Carburetor-Fuel-Problems.pdf
Values not stated here are model-specific; check your owner's manual.