Lower Unit Gasket Kit for Tohatsu/Nissan 8–9.8 HP Outboards – Replaces 3B2-87321-0, 5040536
Lower Unit Gasket Kit for Tohatsu/Nissan 8–9.8 HP Outboards – Replaces 3B2-87321-0, 5040536 is backordered and will ship as soon as it is back in stock.
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Lower Unit Gasket Kit for Tohatsu/Nissan 8–9.8 HP Outboards – Repla...
Lower Unit Gasket Kit for Tohatsu/Nissan 8–9.8 HP Outboards – Replaces 3B2-87321-0, 5040536 is backordered and will ship as soon as it is back in stock.
Product Details
This lower unit gasket kit provides replacement gaskets, O-rings, and oil seals for servicing specified Tohatsu and Nissan 8 HP and 9.8 HP outboard lower units. It covers the model and year applications listed below for 2-stroke M8B, M9.8B, NS8B, and NS9.8B engines and 4-stroke MFS8A2, MFS9.8A2, NSF8A2, NSF9.8A2, MFS8A3, MFS9.8A3, NSF8A3, and NSF9.8A3 engines.
The kit is listed as a replacement for Tohatsu/Nissan part numbers 3B2-87321-0, 3B2873210M, 3B2873211M, 3B2873213M, 3B2873214M, and 3B2873215M. Johnson/Evinrude part number 5040536 is provided as a cross-reference only; specific Johnson/Evinrude model fitment is not confirmed by the compatibility information available for this product.
- Replacement gasket and seal set for lower unit service.
- Model- and year-specific fitment; verify the exact engine model and serial information before ordering.
- Designed as a direct replacement for the listed applications.
- Covered by a 1-year manufacturer warranty as stated for this product.
Part Number Matrix
Use the following references to compare the kit with the part number shown on your original component or service documentation. Part-number references do not replace verification of the engine model, year, and serial number.
| Brand | Part Number | Reference |
|---|---|---|
| Tohatsu/Nissan | 3B2-87321-0 | Primary replacement reference |
| Tohatsu/Nissan | 3B2873210M | Replacement reference |
| Tohatsu/Nissan | 3B2873211M | Replacement reference |
| Tohatsu/Nissan | 3B2873213M | Replacement reference |
| Tohatsu/Nissan | 3B2873214M | Replacement reference |
| Tohatsu/Nissan | 3B2873215M | Replacement reference |
| Johnson/Evinrude | 5040536 | Cross-reference only; model fitment not confirmed |
Engine and Model Compatibility
Confirm the complete engine model, year, and serial number information before installation. Horsepower alone is not sufficient to establish fitment.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Tohatsu | M8B | 8 | 2-Stroke | 2003 | 3B2-87321-0 | Verify model and serial information |
| Tohatsu | M9.8B | 9.8 | 2-Stroke | 2003 | 3B2-87321-0 | Verify model and serial information |
| Nissan | NS8B | 8 | 2-Stroke | 2003 | 3B2-87321-0 | Verify model and serial information |
| Nissan | NS9.8B | 9.8 | 2-Stroke | 2003 | 3B2-87321-0 | Verify model and serial information |
| Tohatsu | MFS8A2 | 8 | 4-Stroke | 2004 | 3B2-87321-0 | Verify model and serial information |
| Tohatsu | MFS9.8A2 | 9.8 | 4-Stroke | 2004 | 3B2-87321-0 | Verify model and serial information |
| Nissan | NSF8A2 | 8 | 4-Stroke | 2004 | 3B2-87321-0 | Verify model and serial information |
| Nissan | NSF9.8A2 | 9.8 | 4-Stroke | 2004 | 3B2-87321-0 | Verify model and serial information |
| Tohatsu | MFS8A3 | 8 | 4-Stroke | 2006, 2009–2014 | 3B2-87321-0 | Verify model and serial information |
| Tohatsu | MFS9.8A3 | 9.8 | 4-Stroke | 2006, 2009–2014 | 3B2-87321-0 | Verify model and serial information |
| Nissan | NSF8A3 | 8 | 4-Stroke | 2006, 2009–2014 | 3B2-87321-0 | Verify model and serial information |
| Nissan | NSF9.8A3 | 9.8 | 4-Stroke | 2006, 2009–2014 | 3B2-87321-0 | Verify model and serial information |
| Johnson/Evinrude | Not specified | Not specified | Not specified | Not specified | 5040536 | Cross-reference only; confirm the original part number and application |
Technical Specifications
- Product Type
- Lower unit gasket kit
- Application
- Specified Tohatsu and Nissan 8–9.8 HP outboards
- Installation
- Direct replacement for listed applications
- Warranty
- 1 year, as stated for this product
What's in the Box
- 3 × Gasket (332-60006-0)
- 1 × O-ring (345-65015-0)
- 1 × Oil seal (369-60111-0)
- 1 × Guide plate gasket (3B2-65029-0)
- 1 × Oil seal (309-60111-0)
- 1 × Lower pump case gasket (3B2-65020-1)
- 1 × O-ring (369-66021-1)
- 1 × O-ring (332-66032-0)
- 1 × Pump case gasket (3B2-65018-0)
Installation Notes
- Disconnect the battery and secure the outboard in an upright position.
- Drain the lower unit gear lubricant completely.
- Disassemble the lower unit carefully, keeping bolts and components organized. Record the location and orientation of each gasket and seal being removed.
- Clean all mating surfaces thoroughly to remove old gasket material, sealant, and corrosion. Surfaces should be clean and dry before installation.
- Install the new gaskets, O-rings, and seals from the kit. Lightly lubricate seals with fresh gear lubricant where specified by the service manual.
- Reassemble the lower unit with all components correctly aligned. Tighten fasteners in the correct sequence and to the manufacturer's specified torque.
- Refill the lower unit with the manufacturer-specified gear lubricant to the correct level, then check for leaks before returning the engine to service.
Troubleshooting and FAQ
How do I know if my lower unit gaskets or seals need replacement?
Common signs include milky or discolored gear lubricant, visible lubricant around the propeller shaft or drain screws, or repeated loss of gear lubricant. These symptoms can have multiple causes, so inspect the lower unit and consult the appropriate service manual.
Will this kit fit any Tohatsu or Nissan 8 or 9.8 HP engine?
No. Fitment is model- and year-specific. Use the compatibility table and verify the complete model and serial number information rather than relying on horsepower alone.
Is additional sealant required?
Installation requirements vary by gasket location and engine model. Install the parts on clean mating surfaces and follow the applicable manufacturer's service manual for sealant requirements and torque specifications.
Is this an OEM kit?
No. This is an aftermarket replacement kit. The listed OEM and manufacturer part numbers are provided as application and cross-reference information.
What does part number 5040536 mean?
5040536 is listed as a Johnson/Evinrude cross-reference. It does not by itself confirm fitment to a particular Johnson/Evinrude engine, so verify the original part number and exact engine application before ordering.
What is the warranty?
This product is stated to include a 1-year manufacturer warranty against manufacturing defects under normal use. Contact the seller with your order information if a warranty issue occurs.
Safety and Important Information
- Verify the engine model, year, serial information, and original part number before ordering.
- Do not rely on horsepower alone to determine compatibility.
- Compare the supplied components with the original parts before beginning disassembly.
- Follow the applicable service manual for torque values, lubricant specifications, sealant requirements, and safe installation procedures.
- Professional installation is recommended when lower unit disassembly or seal replacement is outside your experience.
About Sea Sierra
- Marine Replacement Parts — Replacement components for common marine service and repair applications.
- Application-Focused Fitment — Product information is organized around model, year, horsepower, and part-number verification.
- Service Support — Consult the compatibility information and service documentation before installation.
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