Mercruiser Manifold Assembly Connector Kit – Fits Alpha One Gen 2 and Bravo I/II/III Stern Drives
This manifold assembly connector kit is designed for Mercruiser Alpha One Gen 2 and Bravo I, II, and III stern drives from 1983 and newer. It provides a reliable connection for the stern drive trim system, linking the hydraulic trim lines.
This component is a direct replacement for several OEM and aftermarket parts, ensuring broad compatibility for repairs and maintenance.
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Installation: Connects the hydraulic lines within the stern drive's power trim system.
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Housing Material: Constructed from durable aluminum for corrosion resistance.
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Included Components: Comes with the plate, junction block body, gaskets, lockwashers, and mounting bolts for a complete installation.
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand |
Part Number |
| Mercury / Quicksilver |
8M0137703 |
| Mercury / Quicksilver |
8M0080805 |
| Mercury |
98825A4 |
| Mercury |
98825A12 |
| GLM |
21970 |
| Sterndrive Engineering |
9F-116-17K |
Compatible Engine Models
Confirm your engine model/year in the table below. For Mercruiser owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.
| Brand |
Model |
Rated HP |
Stroke |
Years |
OEM Part No. |
Notes |
| Mercruiser |
Alpha One Gen 2 |
Various |
Various |
1983 and up |
98825A4/8M0137703 |
Stern drive trim connector |
| Mercruiser |
Bravo I |
Various |
Various |
1983 and up |
98825A4/8M0137703 |
Stern drive trim connector |
| Mercruiser |
Bravo II |
Various |
Various |
1983 and up |
98825A4/8M0137703 |
Stern drive trim connector |
| Mercruiser |
Bravo III |
Various |
Various |
1983 and up |
98825A4/8M0137703 |
Stern drive trim connector |
| Mercruiser |
R/MR |
Various |
Various |
1983 and up |
98825A4/8M0137703 |
Stern drive trim connector |
| Mercruiser |
MC-1 |
Various |
Various |
1983 and up |
98825A4/8M0137703 |
Stern drive trim connector |
Technical Specifications
| Specification |
Value |
| Product Type |
Manifold Assembly Connector Kit |
| Installation |
Stern drive trim system connection |
| Connection |
Hydraulic trim line connection |
| Housing Material |
Aluminum |
| Housing Color |
Silver/Metallic |
| Fitting Type |
Threaded manifold assembly |
| Other Technical Attributes |
For stern drive trim systems |
Package Contents
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1 x Plate
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1 x Junction Block Body
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2 x Gaskets
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2 x Lockwashers
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2 x Mounting Bolts
Installation Guide
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Safety First: Disconnect the boat's battery to prevent any electrical accidents.
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Access the Connector: Locate the existing manifold connector assembly on the transom. Access may require tilting the stern drive.
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Prepare for Fluid: Place a drain pan and absorbent rags under the hydraulic lines to catch any spilling trim fluid.
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Disconnect Lines: Carefully loosen and disconnect the hydraulic trim lines from the junction block body.
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Remove Old Assembly: Unfasten the two mounting bolts holding the old manifold assembly and remove it, along with the old gaskets.
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Clean Surface: Thoroughly clean the mounting surface on the transom, removing any old gasket material or corrosion.
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Install New Gaskets: Place the new gaskets onto the new junction block body.
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Mount New Assembly: Position the new manifold assembly and secure it using the new mounting bolts and lockwashers. Tighten to manufacturer-specified torque.
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Reconnect Lines: Re-attach the hydraulic trim lines to the new junction block. Ensure the fittings are tight to prevent leaks.
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Bleed and Refill: Top off the power trim fluid reservoir and bleed the system of any air according to your drive's service manual.
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Test Operation: Reconnect the battery. Operate the trim system up and down several times, checking for smooth operation and any signs of leaks.
Troubleshooting & FAQ
Q: How do I confirm this manifold connector will fit my specific Mercruiser drive?
A: This kit is designed for Mercruiser R/MR, Alpha One Gen 2, and Bravo I/II/III models made from 1983 and onward. The best way to confirm fitment is to match your existing part's number to one of the cross-reference numbers listed (e.g., 8M0137703, 98825A4). Visual comparison with the product images is also recommended.
Q: What are the common symptoms of a failing manifold connector?
A: Signs of failure often include hydraulic fluid leaks around the transom-mounted connector, a spongy or unresponsive trim system, or the inability of the stern drive to hold its trim position. Visual inspection may reveal cracks or corrosion on the housing.
Q: Does this kit include everything needed for the job?
A: This kit includes all the core components for the replacement: the plate, block body, gaskets, bolts, and lockwashers. You will need to supply your own tools and fresh power trim/tilt fluid.
Q: OEM vs. Aftermarket?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.
Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.
Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.
Important Notes
- Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
- This product is an aftermarket replacement part and is not an OEM component.
- Professional installation is recommended to ensure safety and optimal performance.
Why Choose JLM MARINE?
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Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
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Fast Global Shipping: Free delivery worldwide in 5–15 days.
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Direct from Manufacturer: Competitive pricing without compromising quality.