Outboard corrosion and pitting: worn or painted anodes
Compartir
Applies to: Yamaha F-series and all outboards, especially in salt or brackish water
Symptoms
- White powder and bubbling paint on the lower unit
- Pitting on the trim tab or gearcase
- Anodes still shiny and full size after a season (not working)
Why it happens
Sacrificial anodes corrode instead of the engine. When they're worn out, painted over or not grounded, the aluminum gearcase and midsection corrode instead.
How to fix it
- Locate every anode using the manual (trim tab, gearcase, bracket, and inside the engine on many models).
- Replace any anode worn to about half its size.
- Never paint anodes; clean their mounting surfaces to bare metal.
- Check ground straps and continuity to the engine.
Tools and parts
- Anode kit (aluminum or zinc to match your water)
- Multimeter
What the factory service manual covers
Anode locations, inspection intervals, ground continuity. The full procedure, specs and wiring diagrams are in the factory service manual for your machine.