This premium 5-inch Outboard Extension Kit from Bay Manufacturing is engineered for Mercury 3.0L outboards ranging from 200–300 HP. Designed to deliver long-lasting durability, the kit includes stainless steel shafts, corrosion-resistant hardware, and a precision-machined spacer housing cast from the same alloy series used by Mercury for OEM-grade performance.
Perfect for upgrading from 20" to 25" or 25" to 30" shaft configurations, this kit provides a reliable, bolt-on solution for improving performance, correcting cavitation, or matching boat transom height.
Product Features
- Complete 5-inch extension kit for Mercury 3.0L outboards
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Fits the following horsepower & models:
- 200, 225, 250 HP (Optimax, DFI, EFI) – 1999 & newer
- 275, 300 HP 3.0L two-stroke
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Compatible serial ranges:
- 0T667124 & Up – 200 HP Optimax
- 0G283148 & Up – 200, 225, 250 HP Optimax
- 0T944708 & Up – 225, 250 HP EFI
- 0G981393 & Up – 300 HP
- Includes: 5″ housing, driveshaft, shift shaft, water tube, studs, nuts, screw, dowel pins
- Housing available in black or silver, depending on production batch
- Manufactured by Bay Manufacturing
- Adds a true 5 inches to engine shaft length
- Built with stainless steel shafts and OE-grade castings for maximum longevity
Additional Information
- Designed for motors that match all listed horsepower, spline, and serial specifications
- Ideal for restoring proper motor height, reducing cavitation, and improving handling
- Not eligible for return except for warranty claim
- Includes 1-year manufacturer warranty
Shipping Information
Additional shipping fees to Alaska, Hawaii, U.S. Territories, or international destinations will be calculated after checkout.
A PayPal payment request will be emailed for any additional charges.
(Some items may be excluded from international shipping.)
Customer Support
For questions or to confirm compatibility, please email customerservice@marinepartswarehouse.com .
Please include your engine model or serial number to help confirm proper fitment before ordering.
