Yanmar 1GM10 Anode Replacement
Sacrificial anodes are the cheap parts that protect the expensive metal on your Yanmar 1GM10 from galvanic corrosion. Below is the anode we recommend, which 1GM10 variants it fits, a step-by-step video, and answers to the zinc-vs-aluminium question.
Check today’s price on Amazon →
Watch: how to do it (step by step)
How to replace the anode on a Yanmar 1GM10
Yanmar 1GM10 strip down and rebuild.Part one Anode inspection.
Tools Needed
- Screwdriver
- Socket wrench (for the alternator bolts)
- Replacement gasket
- Replacement seal (if needed)
Safety
- Ensure the engine is turned off and cool before starting.
- Wear safety glasses to protect your eyes from debris.
Steps
- Locate the anode on the port side of the engine, behind the alternator.
- Remove the alternator by unscrewing the 10 bolts holding it in place.
- Inspect the anode and determine if it needs replacement.
- If replacing, remove the nut securing the anode.
- Unscrew the anode and remove it from the engine.
- Clean the area where the anode was located.
- Prepare the new anode by placing the rubber ring between the anode and the plate.
- Screw the new anode into place and secure it with the nut.
- Replace the alternator, ensuring the new gasket is in place to avoid damage.
- Tighten the 10 bolts to secure the alternator.
Tips
- It's easier to access the anode if the alternator is removed.
- Have the replacement gasket ready before removing the old anode to avoid damaging it.
- Ensure the new anode is a full-size zinc anode.
Which part do I need for my Yanmar 1GM10?
For most 1GM10 owners the part above (27210-20020) is the right choice. Price tip: the aftermarket numbers are usually noticeably cheaper than the OEM-branded box — it is the same physical part. If you need an exact match, these compatible part numbers also fit:
Show all compatible part numbers (1)
| Part number | Description | Fits | |
|---|---|---|---|
| YAN27210-200200 | Yanmar Zinc | 1GM10 | Find on Amazon → |
Many of these are the same physical part under different brand numbers. Build years are shown where our parts data has them. Where a variant has no years, only the model code is listed. Confirm against your engine plate before ordering.
Frequently asked questions
What anode fits a Yanmar 1GM10?
The Yanmar 1GM10 uses the anode sold as 27210-20020, plus its OEM and aftermarket cross-references (1 compatible numbers are listed above). Confirm the number against your engine's model code and year plate before ordering.
How often should I replace the anode on a Yanmar 1GM10?
Inspect your anodes at least once a season and replace them once they are about half eaten away.
Zinc, aluminium or magnesium anodes?
Zinc and aluminium anodes are for saltwater (aluminium also works in brackish water); magnesium is for freshwater only. Pick one type and use it consistently across the engine — mixing types reduces protection.
What happens if the anodes on a Yanmar 1GM10 wear out?
Galvanic corrosion starts attacking the propeller, gearcase and trim hardware instead — repairs that cost far more than a set of anodes. Anodes are consumables; replacing them on time is the whole point.
How long does an anode change take on a Yanmar 1GM10?
Typically well under an hour with basic hand tools — one of the easiest DIY jobs on the engine. The video above shows where each anode sits.
Related guides
- Yanmar 2GM20 anode
- Yanmar 2QM15 anode
- All Yanmar maintenance guides
- Free Yanmar boat valuation
- Buying a boat? Check whether the asking price is fair
As an Amazon Associate we earn from qualifying purchases — at no extra cost to you. Prices and availability are shown at checkout. This guide is for reference; always follow the engine manufacturer’s service manual.