What do I do if my outboard was submerged?

Motor dunked / submerged · Symptom: Outboard fell in water or boat swamped.

Quick answer: Most often: water in cylinders and electrics. Start here: Do not try to start it — risk of hydrolock. If that doesn't fix it, work through the checks below, and see a marine mechanic if you're unsure.

Likely causes (most to least common)

1. Water in cylinders and electrics

Safe owner checks & fixes

1. Do not try to start it — risk of hydrolock.
2. Yamaha owner's manuals contain "Treatment of submerged motor" — follow it and get to a dealer ASAP.

Parts / tools

Fresh water rinse.

Call a marine mechanic when

Always, as soon as possible (Yamaha and Honda both say get it to a dealer promptly to limit corrosion). Don't try to start it. If you're on the water and unsafe, call TowBoatUS/Sea Tow or the Coast Guard (VHF 16).

Sources

• https://defender.com/assets/pdf/yamaha/f15-f20-2022-owner-s-manual.pdf
• https://www.honda.co.uk/marine/owners/maintenance.html

Values not stated here are model-specific; check your owner's manual.

Related problems

• Why is my outboard gear oil milky?
• Why is there no tell-tale (pee) stream from my outboard?
• Why is my outboard battery not charging?