Rectifier for Yamaha Outboards

High-quality marine-grade aftermarket rectifier for selected Yamaha 9.9 HP, 15 HP, 25 HP, 30 HP, 40 HP and 55 HP 2-stroke outboard engines.

Designed as a replacement for Yamaha 664-81970-61 and related rectifier part numbers.

Suitable for selected:

9.9 HP – 2 Stroke
15 HP – 2 Stroke
25 HP – 2 Stroke
30 HP – 2 Stroke
40 HP – 2 Stroke
55 HP – 2 Stroke

CDI/Sierra's application data confirms this rectifier family across these Yamaha horsepower ranges, although the exact applications vary according to model, year and cylinder configuration.

Replaces Yamaha Part Numbers

664-81970-60-00
664-81970-61
664-81970-61-00
664-81970-62
664-81970-62-00
676-81970-00-00
6E9-81970-70-00
6G1-81970-00-00
6G1-81970-60-00
6G1-81970-61-00
6G1-81970-A0-00

Supersession

664-81970-61-00 → 664-81970-62-00

Yamaha parts data confirms that 664-81970-61-00 has been superseded by 664-81970-62-00.

Fits Selected Yamaha 2-Stroke Outboards

9.9 HP

9.9 HP – 2 Stroke

Selected Yamaha 9.9 HP 2-stroke applications.

CDI lists this rectifier family for selected 9.9 HP 2-cylinder engines, while application catalogues show examples including electric-start models from the early/mid-1990s.

15 HP

15 HP – 2 Stroke

Selected Yamaha 15 HP 2-stroke applications.

Includes selected electric-start and charging-system-equipped models.

25 HP

25 HP – 2 Stroke

Selected Yamaha 25 HP 2-stroke applications, including certain:

25
C25
CV25

The 664-81970 rectifier family appears across multiple 25 HP generations, so the original part number should be checked before ordering.

30 HP

30 HP – 2 Stroke

Selected Yamaha 30 HP 2-stroke applications, including certain:

30
C30
CV30

Important

Not every Yamaha 30 HP uses this rectifier.

Yamaha produced different 30 HP engine generations and electrical systems, so please check the original part number.

40 HP

40 HP – 2 Stroke

Selected Yamaha 40 HP 2-stroke applications, including certain:

C40
CV40

Again, not every Yamaha 40 HP 2-stroke uses this rectifier.

55 HP

55 HP – 2 Stroke

Selected Yamaha 55 HP 2-stroke applications, including certain:

C55
CV55

Application information confirms the 664-81970 rectifier family on selected C55/CV55 engines.

Fitment Summary

Horsepower	Engine Type	Application
9.9 HP	2 Stroke	Selected models
15 HP	2 Stroke	Selected models
25 HP	2 Stroke	Selected models
30 HP	2 Stroke	Selected models
40 HP	2 Stroke	Selected models
55 HP	2 Stroke	Selected models

⚠️ Please Note

The horsepower list is a fitment guide only.

This does NOT mean every Yamaha 9.9–55 HP 2-stroke uses this rectifier.

The safest method is to identify the original Yamaha rectifier number or check compatibility using the complete engine model and serial number.

Product Features

Marine-grade aftermarket rectifier
Suitable for selected Yamaha 2-stroke outboards
Applications from 9.9 HP to 55 HP
Replacement for Yamaha 664-81970-61
Replacement for later 664-81970-62
Converts charging-system AC output to DC
Suitable for applicable battery-charging systems
Direct replacement for compatible applications
New aftermarket replacement part

Rectifier or Regulator / Rectifier?

I would describe this particular product primarily as a RECTIFIER, rather than calling it a voltage regulator/rectifier.

Yamaha's description for 664-81970-61-00 is “Rectifier Assy”, and the superseding 664-81970-62-00 is also described as a rectifier assembly.

This will also help differentiate this product from the larger regulator/rectifier units you have been listing.

⚠️ Important – Check Before Ordering

Do NOT order this rectifier by horsepower or appearance alone.

Yamaha used different charging systems and electrical components across engines of the same horsepower.

Before purchasing, please check:

Engine horsepower
Exact Yamaha model
2-stroke engine type
Engine serial number
Original rectifier part number
Electrical connections
Number and colour of wires
Mounting arrangement

Ideally, match your original part number.

If the rectifier looks the same as the one fitted to your engine, this does not always mean it is the correct part for your outboard.

If you are unsure, contact SSI Marine with your complete engine model and serial number before ordering.

Additional Cross References

This rectifier family has a particularly large number of cross references.

Yamaha:

664-81970-60-00
664-81970-61-00
664-81970-62-00
676-81970-00-00
6E9-81970-70-00
6G1-81970-00-00
6G1-81970-60-00
6G1-81970-61-00
6G1-81970-A0-00

CDI / Sierra:

157-664-61

Recmar:

REC6G1-81970-62

CDI/Sierra cross-reference information supports these Yamaha numbers and the Recmar replacement reference.

Yamaha-Built Mariner Applications

This rectifier family is also cross-referenced to selected older Yamaha-built Mariner outboards.

Mercury / Mariner references include selected:

810937M
814995M
81652M
84329M
8M0060278
8M0091976

CDI/Sierra identifies selected Yamaha-built Mariner applications from approximately 9.9–40 HP for this rectifier family.

Important

I would not put Mariner in the main product title.

Keep the listing focused on Yamaha, but having these cross references in the description and tags may help customers searching by their existing part number.

Aftermarket Replacement Part

This is a high-quality marine-grade aftermarket replacement part.

It is not a genuine Yamaha component.

OEM manufacturer names and part numbers are provided for identification and compatibility reference only.

The rectifier is designed as a replacement for the applicable Yamaha references listed above.

Important When Replacing a Failed Rectifier

If the original rectifier has failed, we recommend checking the charging system before installing the replacement.

Check:

Stator output
Battery condition
Battery terminals
Earth / ground connections
Electrical connectors
Wiring condition
Burnt or corroded terminals

Any damaged, overheated or corroded electrical connections should be repaired before fitting the new rectifier.

Buyer Responsibility

It is the buyer's responsibility to confirm that this part is suitable for their particular outboard before installation.

Please check compatibility using your:

Engine model
Horsepower
Serial number
Original rectifier part number

If you are unsure, contact SSI Marine before ordering. Our technical team will be happy to help identify the correct part.

Why Buy From SSI Marine?

Marine-grade aftermarket & OEM-spec parts
Workshop-tested products
More than 10 years supplying and working with outboard engines
Same-day dispatch before 1 PM Monday–Friday
Royal Mail Tracked 24
UK stock
Collection available from Leigh, Greater Manchester
Technical support from experienced outboard specialists
Workshop open Monday–Friday, 9 AM–5 PM

9.9 HP 15 HP 25 HP 30 HP 40 HP 55 HP Yamaha Outboard 2 Stroke Rectifier 664-81970-61