This Bay Manufacturing 5" Extension Kit is designed for late-model Mercury 25 HP and 30 HP 4-stroke outboards (late 2022 and newer). This kit provides a true 5-inch increase in shaft length, improving stability, control, and propeller efficiency—especially in rough or deep-water environments.
Each Mercury extension kit is engineered using stainless-steel shafts and studs, and the spacer housings are cast from high-grade alloy for exceptional longevity and OEM-level durability.
Product Features
- Adds 5 inches of shaft length
- Fits Mercury 25 HP & 30 HP 4-Stroke models built late 2022 and later
- Updated 4-stud design
- Durable black-painted housing
- Stainless-steel shafts and marine-grade hardware
- Direct bolt-on conversion
- Includes 1-year manufacturer warranty
Compatibility Requirements
Your engine MUST meet all the following criteria to use Kit 305:
| HP | Stroke | Year | Model Details |
|---|---|---|---|
| 25 | 4 | Late 2022 & Later | 4-stud housing |
| 30 | 4 | Late 2022 & Later | 4-stud housing |
Compatible Serial Numbers
- 1R154 & Up
Parts Included
- (1) 5" Extension Housing
- (1) 5" Driveshaft
- (1) 5" Shift Shaft
- (1) 5" Water Tube
- (3) Studs & Nuts
- (1) Bushing
Additional Information
- Some kits may arrive painted black; others may be unpainted with a sandblasted finish depending on production batch.
- Engineered for long service life with premium corrosion-resistant materials.
- These kits are not returnable except for warranty replacement.
Shipping Information
Additional shipping fees to Alaska, Hawaii, U.S. Territories, or international destinations will be calculated after checkout.
A PayPal 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.
