This is an aftermarket replacement built to OEM-level specifications with comparable materials, including neoprene rubber and a brass hub. Our parts are manufactured in an ISO 9002 facility and are batch-inspected for quality and consistency.

Water Pump Impeller Kit – Fits Mercury/Mercruiser 65–225 HP (Replaces 47-89984T5)

$38.50 $61.00

Shipping calculated at checkout.

Water Pump Impeller Kit – Fits Mercury/Mercruiser 65–225 HP (Replaces 47-89984T5) is backordered and will ship as soon as it is back in stock.

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

Free standard shipping on all orders under 1 KG

If you have any questions, feel free to email us at info@sierramarines.com, and we’ll get back to you within 20–36 hours.

Product Details

This Water Pump Impeller Kit – Fits Mercury/Mercruiser 65–225 HP (Replaces 47-89984T5) is an aftermarket replacement designed for a wide range of Mercury/Mercruiser and Force/Chrysler outboard engines from the 1960s to the 1990s. It is also compatible with Mercruiser Alpha One, MR, and pre-Alpha sterndrive units within serial number range 2495186 to 0D469858.

This kit serves as a direct interchange for Mercury part numbers 47-89984T5, 47-89984T4, 47-89984T6, and 47-89984Q5, as well as aftermarket equivalents from Sierra (18-3517, 18-3017), GLM (12120), and Mallory (9-48307).

Installs as a direct OEM-style replacement with no modifications needed.
The 6-blade impeller is constructed from durable neoprene rubber with a corrosion-resistant brass hub.
Includes essential components like the impeller, face plate, gaskets, drive key, and O-rings for a complete service.

Part Number Matrix

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

Brand	Part Number
Mercury	47-89984T5
Mercury	47-89984T4
Mercury	47-89984T6
Mercury	47-89984Q5
Sierra	18-3517
GLM	12120
Mallory	9-48307
Sierra	18-3017

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For Mercury/Mercruiser Outboards: This kit fits a wide variety of 2-stroke models from 65 HP to 225 HP. Please verify your specific model and serial number range.

Model	Rated HP	Stroke	Years	OEM Part No.	Notes
65 HP (4 cylinder)	65	2-Stroke	1963–1976	47-89984T5	Serial 2803562-2874263, 2997439-3293183
70 HP	70	2-Stroke	1961–1967	47-89984T5	Serial 1413611-1436114, 1482212-1503458
75 HP (4 cyl)	75	2-Stroke	1984–1988	47-89984T5	Serial 6432901 & UP
80 HP	80	2-Stroke	1969–1983	47-89984T5	Serial 1355468-3493912
85 HP (4 cyl)	85	2-Stroke	1973–1977	47-89984T5	850XS models
850 XS (4 cyl)	85	2-Stroke		47-89984T5	Serial 3493913-4831998
90 HP (6 cyl)	90	2-Stroke	1978–1986	47-89984T5	Serial 4845301 & UP
95 HP (6 cyl)	95	2-Stroke	1966–1967	47-89984T5
100 HP (1000SS)	100	2-Stroke	1962–1969	47-89984T5
105 HP JET	105	2-Stroke	1994–1995	47-89984T5
110/115/125/135/140/150 HP (6 cyl)	110-150	2-Stroke	1966–1988	47-89984T5	Models 1100/1150/1250/1350/1400/1500
V135 CARB	135	2-Stroke	1986–1988	47-89984T5
V135 EFI	135	2-Stroke	1998	47-89984T5
140 JET	140	2-Stroke	1994–1995	47-89984T5
V150 CARB	150	2-Stroke	1978–1985	47-89984T5
V150 CARB/EFI/DFI	150	2-Stroke	1986–1988	47-89984T5
V150 XR2/4/6, Mag II	150	2-Stroke	1978–1988	47-89984T5
V175 (V1750)	175	2-Stroke	1976–1988	47-89984T5
V175/V200 CARB/EFI/DFI	175-200	2-Stroke	1985–1988	47-89984T5
V200	200	2-Stroke	1978–1981	47-89984T5

For Mercruiser Sterndrives: Fits early model sterndrives including MerCruiser I, R, MR, and Alpha One drives up to 1990. Verify your drive's serial number falls within the specified range.

Model	Years	OEM Part No.	Notes
MerCruiser I (MC1)		47-89984T5	S/N 2495186 & Later
MerCruiser R		47-89984T5
MerCruiser MR		47-89984T5
Alpha One	Up to 1990	47-89984T5	S/N range 6854393-0D469858

Technical Specs

Product Type: Water Pump Impeller Kit
Installation: Direct OEM replacement
Connection: Direct drive shaft mount
Dimensions: Impeller diameter: 59.6 mm (2.35 in)
Impeller height: 33.6–33.8 mm (1.32–1.33 in)
Hub shaft diameter: 22.2 mm (0.87 in)
Weight: 99.3 g (3.5 oz)
Fitting Type: Direct shaft mount
Impeller Details: 6 blade impeller design made of neoprene rubber with brass hub

What’s in the Box

1 x Water Pump Impeller (47-89984/47-30221/47-65960/47-85460)
1 x Face Plate with Gaskets
1 x Drive Key or Pin (28-56654)
1 x Water Tube Guide Sleeve
Multiple x "O" Rings
2 x Gearlube Fill & Vent Screw Seals

Installation Notes

Disconnect the battery before beginning service.
Shift the outboard into the neutral position.
Remove the lower unit (gearcase) by unbolting it from the midsection. Disconnect the speedometer tube if present.
Place the lower unit on a suitable workbench.
Unbolt and remove the water pump housing cover and nylon wear sleeve.
Slide the old impeller off the driveshaft. Remove the old gaskets and face plate, taking care not to scratch the housing surfaces.
Clean all mating surfaces thoroughly, removing any old gasket material or sealant.
Install the new face plate, gaskets, and drive key. Lightly grease the new impeller and the inside of the housing with marine grease.
Install the new impeller, turning the driveshaft clockwise to correctly orient the vanes.
Reinstall the water pump housing and torque the bolts to manufacturer specifications.
Reattach the lower unit to the engine, ensuring the water tube, driveshaft splines, and shift shaft are correctly aligned.
Once assembled, use a water source (flushing muffs) to test the engine and verify a strong, steady water stream from the tell-tale outlet.

Troubleshooting & FAQ

How do I know if this impeller kit fits my engine?

Check the Engine & Model Compatibility tables on this page. It's crucial to match your engine's model, horsepower, and especially the serial number range. When in doubt, compare the photos and dimensions to your existing part before ordering.

What are the signs of a failing water pump impeller?

Common signs include a weak, intermittent, or non-existent water stream from the "tell-tale" outlet at idle, engine overheating alarms, and in severe cases, steam from the exhaust. Do not run an engine that is not pumping water.

How often should I replace my impeller?

For preventative maintenance, it's recommended to inspect the impeller annually and replace it every 1-2 years (or 100-200 hours), regardless of appearance. Use in saltwater or sandy/silty conditions may require more frequent replacement.

My engine is overheating, but the tell-tale stream looks okay. Could it still be the impeller?

Yes. A strong tell-tale stream only indicates that the pump is moving some water, not necessarily enough volume to cool the entire engine block under load. A worn impeller can lose efficiency, or there could be a blockage in the cooling passages.

Is the included drive key important?

Yes, the drive key is critical. It locks the impeller to the driveshaft, forcing it to spin. A missing or sheared key will result in the impeller not turning, leading to immediate overheating. This kit includes the necessary key.

Why is a brass hub better than a plastic one?

A brass hub provides superior durability and resistance to heat and stripping, especially in high-horsepower or demanding commercial applications. It creates a stronger bond with the driveshaft, preventing the impeller from spinning freely on the shaft (a common failure point for plastic hubs).

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials, including a neoprene rubber compound and a brass hub. Our parts are manufactured in an ISO 9002 facility and are batch-inspected for quality and consistency.

Shipping speed & cost

We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free for most regions. Expedited shipping options will appear at checkout if they are available for your location.

Warranty & returns

Our parts are covered by a 1-year warranty against manufacturing defects under normal marine use. If you encounter an issue, please contact our support team with your order details. Returns are accepted within our standard window for unused items in their original condition. See our full policy page or reach out for instructions.

Safety & Important Info

Verify images and specifications against your original part before purchasing. If anything differs—even if your model appears on a compatibility list—do not purchase.
This is an aftermarket replacement part, not an original equipment manufacturer (OEM) component. Brand names and part numbers are used for reference purposes only.
Professional installation by a qualified marine mechanic is highly recommended for safety and to ensure proper performance.

About Sea Sierra

Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and rigorously tested for real-world saltwater and freshwater conditions.
Fast Global Fulfillment — With our streamlined logistics, we offer free standard delivery to most regions, with typical transit times of just 5–15 days.
Manufacturer-Direct Value — By cutting out the middlemen, we deliver exceptional quality and QC without the traditional dealership markup, offering fair pricing on every part.

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.