Lower Unit Seal Kit – Fits Force 9.9, 12, 15 HP (1979–1984) (Replaces FK1065)
Lower Unit Seal Kit – Fits Force 9.9, 12, 15 HP (1979–1984) (Replaces FK1065) is backordered and will ship as soon as it is back in stock.
Couldn't load pickup availability
Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Lower Unit Seal Kit – Fits Force 9.9, 12, 15 HP (1979–1984) (Replac...
Product Details
This is a complete Lower Unit Seal Kit – Fits Force 9.9, 12, 15 HP (1979–1984) (Replaces FK1065), designed to restore the gearcase of your outboard. It is built for a precise fit on Force 9.9 HP (1979–1984), 12 HP (1979), and 15 HP (1979–1984) 2-Stroke engines, replacing OEM part number FK1065.
It serves as a direct interchange for SEI 95-750-11K, GLM 87804, and Sierra 18-2638, providing a reliable aftermarket alternative.
- Prevents water intrusion and oil leaks in the lower gearcase.
- Engineered to meet or exceed original factory specifications.
- Professional installation is recommended for optimal performance and longevity.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Force (OEM) | FK1065 |
| SEI Marine Products | 95-750-11K |
| GLM | 87804 |
| Sierra | 18-2638 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Force | Outboard | 9.9 HP | 2-Stroke | 1979–1984 | FK1065 | |
| Force | Outboard | 12 HP | 2-Stroke | 1979 | FK1065 | |
| Force | Outboard | 15 HP | 2-Stroke | 1979–1984 | FK1065 |
Technical Specs
- Product Type
- Lower Unit Gearcase Seal Kit
- Weight
- 0.91 kg (2 pounds)
- Product Dimensions
- 7.0" L x 6.0" W x 0.63" H
- Replaces OEM Part
- FK1065
Installation Notes
Professional installation is highly recommended. The general steps are as follows:
- Drain the gearcase oil completely. Inspect the old oil for metal shavings or a milky appearance, which indicates water intrusion.
- Disassemble the lower unit to access the driveshaft and prop shaft seals. This typically involves removing the propeller, bearing carrier, and water pump housing.
- Carefully remove all old seals, gaskets, and O-rings, taking care not to scratch the housing surfaces.
- Thoroughly clean all sealing surfaces to ensure they are free of old adhesive, corrosion, or debris.
- Install the new seals and O-rings from the kit using appropriate seal drivers. Lubricate seals with marine grease before installation.
- Reassemble the lower unit, ensuring all components are torqued to the manufacturer's specifications.
- Perform a pressure and vacuum test on the gearcase to confirm the new seals are properly seated and holding.
- Refill the gearcase with fresh, high-quality lower unit lubricant to the correct level.
Troubleshooting & FAQ
How do I know if my lower unit seals are failing?
Common signs include milky, grey gear lube (indicating water has mixed with the oil), visible oil leaks around the propeller shaft or driveshaft, or metal shavings in the drained oil, which can result from corrosion caused by water intrusion.
Is this kit compatible with a Chrysler-branded engine?
Yes, this kit fits specific early Force outboards, which were derived from Chrysler Marine designs. It is compatible with the Force models and years listed in the compatibility table.
Do I need special tools for this installation?
Yes, installation typically requires a seal puller, seal drivers or sockets of the correct size to press in the new seals without damaging them, and a gearcase pressure tester. Professional installation is recommended to ensure a leak-free result.
How often should lower unit seals be replaced?
There is no fixed interval, but seals should be inspected annually when you change the gear lube. It's good practice to replace them if you notice any signs of leakage or if the outboard is more than 5-7 years old and they have never been changed, especially if used in saltwater.
What is the difference between this kit and the OEM version?
This aftermarket kit is designed to meet or exceed OEM specifications for fit and function, using comparable materials. The primary difference is the price point, offering a cost-effective solution for repairs.
Can I install this myself?
While possible for experienced mechanics, we strongly recommend professional installation. An improper seal installation can lead to catastrophic gearcase failure, which is a much more expensive repair.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
