Lower Casing Cap for Yamaha F25 and C30 Outboards – Replaces 61N-45361

Product Details

This aftermarket lower casing cap is intended for selected Yamaha F25 and C30 outboard lower-unit applications. It is designed for the lower casing drive assembly and is listed as a replacement for Yamaha OEM reference 61N-45361.

The cap is supplied as the replacement component described in this listing. Bearings, oil seals, O-rings, fasteners, and other service parts are not included unless specifically shown or stated by the seller.

• Replacement lower casing cap for selected Yamaha F25 and C30 outboards
• For lower casing drive assembly service
• Reference OEM number: 61N-45361
• Not intended for applications using the different 6L2 lower casing cap specification

Part Number Reference

Use the reference below to compare the part removed from your engine before ordering.

Engine and Model Compatibility

The available product information identifies Yamaha 25HP F25-series and 30HP C30 applications. Model suffixes, production years, shaft lengths, and lower-unit configurations can affect fitment, so compare the original cap and verify the OEM reference before purchase.

Technical Specifications

Part type

Lower casing cap

OEM reference

61N-45361

Application

Lower casing drive assembly

Listed engine families

Yamaha F25 and C30

Power class

25HP and 30HP

Exclusion

Do not use for 6L2 applications unless the dimensions and part reference are confirmed

What's in the Box

• Lower casing cap × 1

Bearings, seals, O-rings, gaskets, hardware, and lubricants are not included as separate components unless specifically shown in the product package supplied with your order.

Installation Notes

1. Disconnect the battery and remove the lower unit according to the applicable manufacturer's service manual.
2. Drain the lower-unit gear oil and clean the exterior of the assembly.
3. Remove the existing lower casing cap, keeping track of the orientation and location of any serviceable components.
4. Inspect the cap seat, bearing bores, seals, bearings, and surrounding housing for wear, corrosion, or damage.
5. Transfer or replace service components only when permitted by the service manual. Replacement bearings, seals, and O-rings are not included with this cap.
6. Clean the mating surfaces and confirm that the replacement cap matches the original dimensions and reference.
7. Install the cap using the correct sealant, fasteners, alignment procedure, and torque specifications for the engine.
8. Refill the lower unit with the specified gear oil and check for leaks before returning the engine to service.

Because lower-unit service requires correct alignment and torque, professional installation is recommended when suitable tools and the service manual are not available.

Troubleshooting & FAQ

How do I confirm that this cap fits my engine?

Compare the cap removed from your engine with the product dimensions and confirm OEM reference 61N-45361. Also verify the exact model suffix, year, lower-unit configuration, and mounting arrangement before ordering.

Is this a complete rebuild kit?

No. The product record identifies this item as the lower casing cap component. Bearings, oil seals, O-rings, gaskets, and other service parts are not included unless separately stated in the order.

Which engines are listed for this replacement?

The available application information identifies selected Yamaha F25 25HP and C30 30HP outboards. Exact fitment depends on the lower-unit configuration and OEM reference.

Can this replace a 6L2 lower casing cap?

Do not assume interchangeability. The 6L2 reference uses a different specification, including different dimensional requirements. Confirm the exact part number and measurements before ordering.

What are common signs that the lower casing cap needs service?

Possible signs include gear-oil leakage, bearing noise, rough operation, corrosion, or visible wear around the cap and its sealing surfaces. Inspect the complete lower-unit assembly before replacing one component.

Is this an OEM component?

This listing is for an aftermarket replacement component, not a Yamaha-branded OEM part. Yamaha and other manufacturer names and part numbers are used only to identify the intended application and reference.

Safety & Important Information

• Verify the original part number, dimensions, model suffix, and lower-unit configuration before purchase.
• Do not rely on horsepower alone to confirm fitment.
• Use the applicable service manual for disassembly, sealant, alignment, oil capacity, and torque specifications.
• Stop installation if the replacement part does not match the original component or if the housing shows damage.

About Sea Sierra

• Marine replacement parts selected for practical service and repair applications.
• Product information is provided to help customers compare part references and engine applications.
• For the best fit, verify the original component and complete engine identification before ordering.