Genuine Tohatsu Piston Pin 309-00021-1 2.5/3.5HP 2-Stroke
309-00021-1
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Tohatsu Piston Pin
Genuine 309-00021-1 | 2.5/3.5HP two-stroke
Genuine Tohatsu piston pin (wrist pin) for the specified 309-series piston assemblies used in small 2.5HP and 3.5HP two-stroke outboards. It connects the piston to the connecting rod and must be checked with the correct piston, bearing and retaining clips.
Key Features
- ✔ Genuine Tohatsu OEM piston pin
- ✔ Current -1 service reference
- ✔ For selected 2.5/3.5HP two-stroke assemblies
- ✔ Precision internal-engine component
- ✔ Sold as one piston pin
Technical Specs
| Part type | Piston / wrist pin |
| Engine cycle | 2-stroke |
| Power family | 2.5HP / 3.5HP |
| Manufacturer number | 309-00021-1 |
| Quantity | 1 pin |
| 4Boats SKU | 309-00021-1 |
Compatibility / Fitment Guide
Verified base engine family: Tohatsu M2.5A2, M3.5A2 and M3.5B2 and Nissan Marine NS2.5A2, NS3.5A2 and NS3.5B2 two-stroke outboards, only where the serial-specific piston/crankshaft diagram lists the exact part number in this listing.
Component match: confirm the piston, small-end bearing/rod and retaining-clip references in the same diagram. Clips are separate unless visibly included.
Identification rule: read the model and serial plate, then check the correct internal-engine diagram. Similar-looking 309, 3F0, 302, 361 and other numbered parts are not interchangeable by appearance.
Exclusions: not for MFS5, MFS6, MFS8, MFS9.8 or MFS15; not for larger two-strokes; and not for another piston family with a similar-looking pin.
Part Number Cross Reference
| Tohatsu current | 309-00021-1 / 309000211M |
| Superseded Tohatsu | 309-00021-0 / 309000210M |
| Retaining clip family | 309-00024-1 (verify separately) |
| 4Boats SKU | 309-00021-1 |
A supersession confirms the pin reference, not that clips or bearings are included.
Frequently Asked Questions
Is it genuine Tohatsu?
Yes. The listing is for one genuine Tohatsu piston pin.
Does it fit MFS5A through MFS15A?
No. The previous description was incorrect; this is for the specified 2.5/3.5HP two-stroke family.
Are retaining clips included?
No clips should be assumed included unless they are clearly shown in the product photographs.
Can the old pin be reused?
Measure and inspect it with the piston and small-end components according to the service limits; replace any worn or damaged parts.
Note: Use new retaining clips where specified and ensure each clip is fully seated with its gap positioned according to the service procedure.
For the products under £150 the shipping is £6.99.
Free delivery for most items over £150.
