Lower Unit Seal Kit for Honda BF75/BF90 Outboard Motors – 5-Seal Set, Pin and One Washer Not Included
Lower Unit Seal Kit for Honda BF75/BF90 Outboard Motors – 5-Seal Set, Pin and One Washer Not Included is backordered and will ship as soon as it is back in stock.
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Lower Unit Seal Kit for Honda BF75/BF90 Outboard Motors – 5-Seal Se...
Lower Unit Seal Kit for Honda BF75/BF90 Outboard Motors – 5-Seal Set, Pin and One Washer Not Included is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket Lower Unit Seal Kit for Honda BF75/BF90 outboard motors is intended for lower-unit and gearcase resealing service. The set contains five commonly replaced seals for the driveshaft, propeller shaft, and shift shaft.
Important package notice: this listing includes the five seals described below, but it does not include the required pin or one washer. Confirm that you already have those parts, or source them separately, before beginning installation.
- Five-seal lower-unit service set.
- Intended for specified Honda BF75 and BF90 4-Stroke gearcases.
- Aftermarket replacement parts; not genuine Honda components.
- Does not include a pin or one washer.
Part Number References
The following numbers are reference points for comparing the seals and aftermarket applications. Always verify the complete engine model, year, serial range, and original seal dimensions before ordering.
| Brand | Part Number | Reference Description |
|---|---|---|
| Sierra | 18-8366 | Aftermarket lower-unit seal kit reference |
| Honda | 91251-ZW1-003 | Driveshaft seal reference |
| Honda | 91252-ZW1-003 | Propeller-shaft inner seal reference |
| Honda | 91253-ZW1-003 | Shift-shaft seal reference |
| Honda | 91254-ZW1-003 | Driveshaft oil-seal reference |
| Honda | 91255-ZW1-003 | Propeller-shaft outer seal reference |
Engine and Model Compatibility
The available product information identifies this seal set for Honda BF75 and BF90 4-Stroke outboards. Compatibility can vary by gearcase design, production year, and serial number, so compare the references with your service manual before installation.
| Brand | Model | Rated HP | Stroke | Reference Application | Notes |
|---|---|---|---|---|---|
| Honda | BF75 | 75 HP | 4-Stroke | Lower unit / gearcase | Verify year, serial range, and existing seal references. |
| Honda | BF90 | 90 HP | 4-Stroke | Lower unit / gearcase | Verify year, serial range, and existing seal references. |
Technical Specifications
- Product Type
- Aftermarket lower-unit seal kit
- Application
- Honda BF75/BF90 4-Stroke outboard gearcases, subject to model and serial verification
- Seal Quantity
- Five seals
- Installation
- Replacement service requiring lower-unit disassembly
- Excluded Components
- Pin and one washer are not included
What's in the Box
- 1 x Driveshaft seal, reference 91251-ZW1-003
- 1 x Propeller-shaft inner seal, reference 91252-ZW1-003
- 1 x Shift-shaft seal, reference 91253-ZW1-003
- 1 x Driveshaft oil seal, reference 91254-ZW1-003
- 1 x Propeller-shaft outer seal, reference 91255-ZW1-003
- Not included: one pin and one washer
Installation Notes
- Secure the outboard according to the manufacturer's service instructions and drain the gearcase lubricant into a suitable container.
- Remove the lower unit from the driveshaft housing.
- Remove the applicable propeller-shaft, driveshaft, and bearing-carrier components to access the seals.
- Remove the old seals carefully without scratching the seal bores or mating surfaces.
- Clean each seal seat and remove corrosion, debris, and old sealant.
- Check that the required pin and washer are available before reassembly; they are not supplied with this listing.
- Lightly lubricate the replacement seals with suitable marine grease or gear lubricant, as specified by the service manual.
- Use the correct seal driver or a properly sized socket to install each seal squarely to the specified depth.
- Reinstall the bearing carriers, propeller shaft, driveshaft, and other removed components in the correct order.
- Reattach the lower unit, ensuring proper driveshaft and water-tube alignment.
- Refill the gearcase with the manufacturer's recommended lubricant and check for leaks before returning the outboard to service.
Troubleshooting and FAQ
How do I confirm that this seal set fits my Honda outboard?
Check that your engine is a Honda BF75 or BF90 4-Stroke and compare the model year, serial range, gearcase configuration, and seal references with the service manual or the parts removed from your engine. A model name alone is not sufficient for every production range.
What is included in this listing?
The listing contains five lower-unit seals: one driveshaft seal, one propeller-shaft inner seal, one shift-shaft seal, one driveshaft oil seal, and one propeller-shaft outer seal.
Are the pin and washer included?
No. One pin and one washer are not included. Obtain the correct replacement parts separately before starting the repair.
What are common signs of a lower-unit seal problem?
Water-contaminated gear lubricant may appear milky or cloudy, while lubricant leaks may appear around the propeller shaft, driveshaft, or shift-shaft areas. Inspect the gearcase and investigate leaks before continued operation.
Can I replace only one seal?
A single failed seal can sometimes be replaced independently, but the accessible seals should be inspected during disassembly. Replace all damaged or worn seals and follow the service manual's procedure.
What additional items may be needed?
Depending on the repair, you may need the correct pin, washer, drain and fill screw gaskets, marine gear lubricant, sealant specified by the service manual, a seal-removal tool, and correctly sized seal drivers.
Is this an OEM product?
No. This is an aftermarket replacement seal set. The listed Honda and Sierra numbers are reference numbers for comparison and application checking.
Safety and Important Information
- Verify the engine model, year, serial range, gearcase configuration, and reference numbers before purchase.
- Do not operate the outboard if the gearcase contains water-contaminated lubricant or has an active lubricant leak.
- The pin and one washer are excluded from the package; do not assume this is a complete hardware kit.
- Use the manufacturer's service manual for torque values, seal depth, lubricant type, and reassembly procedures.
- Professional installation is recommended when lower-unit disassembly or bearing-carrier service is required.
About Sea Sierra
- Pro-Grade Standards — We supply marine replacement parts selected for practical service and real-world operating conditions.
- Global Fulfillment — Standard and expedited delivery options are shown at checkout where available.
- Manufacturer-Direct Value — Competitive pricing focused on dependable aftermarket replacement solutions.
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