Aftermarket Lower Unit Oil Seal for Yamaha F40G, F70A, F80A/B & F100A/D | OEM 93101-25M03

Product Details

This aftermarket lower unit oil seal is intended for selected Yamaha four-stroke outboard applications. The listed fitment includes Yamaha F40G, F70A, F80A, F80B, F100A, and F100D models. The seal is used in the gearcase oil-sealing system to help retain lubricant and limit water or contaminant entry when correctly matched to the engine and lower-unit assembly.

This replacement seal corresponds to Yamaha OEM reference 93101-25M03. It is supplied as an individual oil seal, not as a complete gearcase seal kit or lower-unit assembly.

• Aftermarket replacement for the listed application
• Designed for use in the lower unit or gearcase oil-sealing system
• Single replacement seal for service or repair
• Confirm the original seal reference and engine identification before ordering

Part Number Reference

The following manufacturer reference is associated with this oil-seal application.

Engine & Model Compatibility

The product listing identifies the following Yamaha four-stroke model applications. Year, shaft length, lower-unit version, and serial-number ranges were not provided, so verify those details against your engine and original part before installation.

Technical Specifications

Product type

Individual aftermarket oil seal

Application

Yamaha lower unit or gearcase oil-sealing service

Manufacturer reference

93101-25M03

Engine type

Selected Yamaha four-stroke outboards listed above

Fitment scope

Model fitment is listed; verify year, serial number, lower-unit configuration, and original part before purchase

What's in the Box

• 1 x Lower Unit Oil Seal

Installation Notes

Installation should follow the service procedure for the specific Yamaha engine and lower-unit configuration. The exact access procedure can vary by model and gearcase design.

1. Confirm the original seal, manufacturer reference, and engine identification before beginning work.
2. Drain the lower-unit gear oil and remove the propeller and related hardware as required by the service procedure.
3. Remove the lower unit or the applicable gearcase components according to the manufacturer service manual.
4. Remove the old seal carefully without damaging the shaft, seal bore, bearing carrier, or adjacent components.
5. Clean the seal bore and inspect the shaft and surrounding surfaces for scoring, corrosion, wear, or debris.
6. Lubricate the new seal lip with the lubricant specified by the service manual.
7. Install the seal squarely with a suitable seal driver, at the position specified for the application.
8. Reassemble the lower unit using required gaskets, fasteners, and torque specifications.
9. Refill the gearcase with the manufacturer-specified gear lubricant and check for leaks after service.

Troubleshooting & FAQ

What does this product replace?

This is an aftermarket replacement associated with Yamaha manufacturer reference 93101-25M03. Always compare the number and physical dimensions of the original seal before installation.

Which Yamaha engines are listed for this seal?

The listed applications are Yamaha F40G, F70A, F80A, F80B, F100A, and F100D four-stroke outboards. Year, serial-number, shaft-length, and lower-unit configuration details are not included in the available application data.

Is this a complete lower-unit seal kit?

No. This listing is for one individual lower unit oil seal. It does not include a propeller, shaft, bearings, O-rings, gaskets, additional seals, or other gearcase components.

What can cause a replacement seal to leak?

Leaks may result from a scored or worn shaft, corrosion or damage in the seal bore, incorrect installation depth, a damaged seal lip, contaminated lubricant, or wear in nearby bearings or gearcase components. Inspect the complete sealing area before replacing the seal.

Can I install it without checking the service manual?

Use the service manual for the exact engine and lower-unit configuration. Seal access, installation position, lubricant requirements, fastener torque, and reassembly steps can vary between applications.

Is this an OEM component?

No. This is an aftermarket replacement associated with Yamaha manufacturer reference 93101-25M03. Yamaha is a trademark of its respective owner; this product is not represented as a Yamaha-manufactured part.

How should I confirm fitment?

Compare the original seal reference, engine model, year, serial number, lower-unit version, and physical seal dimensions. Do not rely on horsepower alone when confirming compatibility.

Safety & Important Information

• Verify the manufacturer reference and all engine identification details before ordering.
• Do not install a seal if the shaft, bore, bearing carrier, or surrounding components are damaged.
• Use the correct lubricant, installation position, and torque specifications from the applicable service manual.
• Professional installation is recommended when lower-unit disassembly or gearcase service is required.
• This is an aftermarket replacement, not an OEM component.

About Sea Sierra

• Marine replacement parts for routine service and repair applications.
• Product information is organized around manufacturer references and listed engine applications.
• Check the current store policy for shipping, warranty, and return information before purchase.