Water Pump Repair Kit – Fits Mercury/Mariner & MerCruiser Alpha One (Replaces 46-96148Q8, 46-96148A8, 46-96148T8)

$25.99

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Water Pump Repair Kit – Fits Mercury/Mariner & MerCruiser Alpha One (Replaces 46-96148Q8, 46-96148A8, 46-96148T8) is backordered and will ship as soon as it is back in stock.

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Product Details

This Water Pump Repair Kit – Fits Mercury/Mariner Outboards & MerCruiser Alpha One (Replaces 46-96148Q8, 46-96148A8, 46-96148T8) provides the essential components needed to service your engine's cooling system. It is designed for a broad range of Mercury/Mariner outboards from 65 to 225 HP (4-cylinder through V-6 models with short-vane impellers) and MerCruiser I, R, MR, and Alpha One stern drives manufactured from 1970 to 1990 (serial numbers 2491586 to 0D469858).

It serves as a direct interchange for Mercury part numbers 46-96148Q8, 46-96148A8, 46-96148T8, 46-96148A5, and 46-96148B8, as well as aftermarket equivalents from Sierra, EMP, and GLM.

Engineered for direct replacement of the upper water pump housing.
Includes all necessary gaskets, seals, and a new impeller for a complete upper-end service.
Kit specifically addresses the impeller and upper housing; it does not include the water pump base.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Brand	Part Number
Mercury	46-96148Q8
Mercury	46-96148A8
Mercury	46-96148T8
Mercury	46-96148A5
Mercury	46-96148B8
Sierra	18-3217
Sierra	18-3316
Sierra	18-3517
EMP	46-00090
EMP	46-00091
GLM	12280

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For Mercury and Mariner outboards, this kit fits various 4-cylinder and V-6 models. Ensure your engine falls within the specified horsepower and year ranges.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Mercury	65	65 HP	2-Stroke	1972–1985	46-96148A8	4-cylinder with aluminum water pump
Mercury	65	65 HP	2-Stroke	1972–1985	46-96148A8	4-cylinder with plastic water pump
Mercury	70	70 HP	2-Stroke	1976–1989	46-96148A8	6-cylinder models
Mercury	75	75 HP	2-Stroke	1975–1998	46-96148A8	4-cylinder models
Mercury	80	80 HP	2-Stroke	1978–1989	46-96148A8	4-cylinder & 6-cylinder models
Mercury	85	85 HP	2-Stroke	1973–1989	46-96148A8	4-cylinder models, including 850 XS
Mercury	90	90 HP	2-Stroke	1978–1998	46-96148A8	6-cylinder models, including 900
Mercury	95	95 HP	2-Stroke	1978–1989	46-96148A8	6-cylinder models, including 950
Mercury	100	100 HP	2-Stroke	1975–1995	46-96148A8	6-cylinder models, including 1000
Mercury	115	115 HP	2-Stroke	1976–1998	46-96148A8	6-cylinder models
Mercury	125	125 HP	2-Stroke	1984–1998	46-96148A8	6-cylinder models
Mercury	135	135 HP	2-Stroke	1976–1992	46-96148A8	V-6 models
Mercury	140	140 HP	2-Stroke	1976–1992	46-96148A8	V-6 models, including 140 Jet
Mercury	150	150 HP	2-Stroke	1976–2000	46-96148A8	V-6 models, including V-150 Carb, EFI, DFI
Mercury	175	175 HP	2-Stroke	1976–2000	46-96148A8	V-6 models
Mercury	200	200 HP	2-Stroke	1976–2000	46-96148A8	V-6 models, 2.5L Carb & EFI
Mercury	220	220 HP	2-Stroke	1984–1989	46-96148A8	V-6 Laser models
Mariner	V-135 to V-200	135-200 HP	2-Stroke	1976–2000	46-96148A8	Various V-6 models

For MerCruiser stern drives, this kit applies to pre-Alpha and Alpha One models within the specified serial number range.

Brand	Model	Years	OEM Part No.	Notes
MerCruiser	I	1970–1983	46-96148A8	Serial numbers 2491586-0D469858
MerCruiser	R	1976–1983	46-96148A8	Serial numbers 2491586-0D469858
MerCruiser	MR	1976–1983	46-96148A8	Serial numbers 2491586-0D469858
MerCruiser	Alpha One	1983–1990	46-96148A8	Serial numbers 2491586-0D469858

Technical Specs

Product Type: Water Pump Repair Kit (Upper Housing)
Installation: Direct replacement
Housing Material: Plastic (upper housing)
Housing Color: Black
Dimensions: 107 × 99 × 102 mm (4.25 × 3.9 × 4.02 in)
Weight: 0.272 kg (0.8 lb)
Warranty: Manufacturer's standard warranty
Other Technical Attributes: Includes components for upper housing repair - does not include water pump base

What’s in the Box

1 x Water Pump Impeller (47-89984T-3)
1 x Plastic Pump Housing Assembly
1 x Face Plate
1 x Gasket Set (multiple gaskets)
1 x Drive Key
1 x Face Seal
1 x Seal Carrier
1 x Water Tube Coupling
1 x O-ring Set (multiple O-rings)
2 x Gear Lube Fill & Vent Screw Seals

Installation Notes

Disconnect the battery and ensure the engine is off and cool.
Drain the gearcase lubricant from the lower unit.
Remove the lower unit (gearcase) from the outboard motor or stern drive.
Unbolt and remove the old water pump housing assembly.
Carefully note the orientation of the old impeller vanes before removing it.
Clean the mounting surfaces, driveshaft, and water pump base thoroughly.
Install the new drive key, impeller, face plate, and gaskets as provided in the kit.
Lubricate the new impeller and housing interior with a marine-safe lubricant.
Install the new housing, ensuring the impeller vanes are oriented correctly (typically clockwise).
Torque the housing bolts to the manufacturer's specification.
Reinstall the lower unit, refill the gearcase with fresh lubricant, and reconnect the battery.
Test the engine using a water supply (flushing muffs) to verify proper water flow from the tell-tale port.

Troubleshooting & FAQ

How do I know if this kit fits my engine?

Confirm your model, year, and (if available) serial number against the compatibility tables above. This kit is designed for specific Mercury/Mariner outboards (65-225 HP) and MerCruiser drives (1970-1990, S/N 2491586–0D469858). Visually comparing your old pump housing to our product images is also a reliable check.

What are the signs of a failing water pump?

Common symptoms include the engine overheating at idle or low speeds, a weak or non-existent water stream from the "tell-tale" outlet port, and in severe cases, steam from the exhaust. An impeller that is brittle, cracked, or has broken vanes needs immediate replacement.

How often should the water pump impeller be replaced?

As a preventative maintenance item, most manufacturers recommend replacing the impeller every 1-2 years or every 100-200 hours of use, whichever comes first. Usage in saltwater or sandy/silty conditions may require more frequent service.

Does this kit include the lower water pump base?

No, this is an upper repair kit. It includes the impeller, upper plastic housing, face plate, gaskets, and associated seals. The metal water pump base is not included.

My engine is still overheating after installing the new kit. What else could be the problem?

If a new water pump doesn't solve an overheating issue, check for other blockages in the cooling system. Common culprits include clogged thermostats, debris in the engine's water passages, or a blocked water intake screen on the lower unit.

Is this a complete kit for the entire water pump?

This is a comprehensive repair kit for the most common wear items (impeller, housing, gaskets). However, it does not include the metal water pump base or other components of the lower unit. It contains everything shown in the pictures and listed under "What's in the Box."

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.

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