Water Pump Impeller – Fits Mercury Marine/Mercruiser 65-300 HP (Replaces 47-89984T4)

$24.50 $39.00

Shipping calculated at checkout.

Water Pump Impeller – Fits Mercury Marine/Mercruiser 65-300 HP (Replaces 47-89984T4) 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 – Fits Mercury Marine/Mercruiser 65-300 HP (Replaces 47-89984T4) is engineered for a broad range of Mercury Marine/Mariner outboards from 65 to 300 HP (model years from the 1970s–1990s) and Mercruiser Alpha One (Gen 1) sterndrives (1983–1990). It is a critical component for maintaining proper engine cooling and preventing overheating.

It serves as a direct interchange for Mercury Marine part numbers 47-89984T4, 47-89984T3, 47-89984, 47-F694065, 47-803631T, 47-8M0028376, 47-65960, 47-85460, 47-30221, and Sierra 18-3017.

Designed for direct-fit internal installation inside the water pump housing.
Constructed from durable neoprene rubber with a metal alloy hub to withstand the marine environment.
Package includes the impeller only.

Part Number Matrix

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

Brand	Part Number
Mercury Marine	47-89984T4
Mercury	47-89984T3
Mercury	47-89984
Mercury	47-F694065
Mercury	47-803631T
Mercury	47-8M0028376
Mercury	47-65960
Mercury	47-85460
Mercury	47-30221
Sierra	18-3017

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This impeller fits a wide range of Mercury Outboards, including many 4-cylinder, 6-cylinder, and V6 models. Check your engine's serial number against the ranges provided.

Model	Rated HP	Stroke	Years	OEM Part No.	Notes
65 HP 4 cylinder	65	2-Stroke	1542745–3293183	47-89984T4	Serial number range
70 HP	70	2-Stroke	1413611–1566239	47-89984T4	Serial number range
75 HP 4 cylinder	75	2-Stroke	6432901-UP	47-89984T4	Serial number range
80 HP	80	2-Stroke	1355468–3493912	47-89984T4	Serial number range
80 HP 4 cylinder	80	2-Stroke	4831999–6432900	47-89984T4	Serial number range
85 HP	85	2-Stroke	1460999–4831998	47-89984T4	Serial number range
85 HP 4 cylinder	85	2-Stroke	4590512-UP	47-89984T4	Serial number range
90 HP	90	2-Stroke	1766824–1869775	47-89984T4	Serial number range
90 HP 6 cylinder	90	2-Stroke	4845301-UP	47-89984T4	Serial number range
95 HP	95	2-Stroke	1869776–2318585	47-89984T4	Serial number range
100 HP 6 cylinder	100	2-Stroke	1464949–3253111	47-89984T4	Serial number range
105 HP JET	105	2-Stroke	D182000-UP	47-89984T4	Serial number range
110 HP	110	2-Stroke	1870204–2314955	47-89984T4	Serial number range
115 HP	115	2-Stroke	2836019-UP	47-89984T4	Serial number range
115 HP 6 cylinder	115	2-Stroke	4694237-UP	47-89984T4	Serial number range
125 HP	125	2-Stroke	2314956–3253111	47-89984T4	Serial number range
135 HP	135	2-Stroke	2839369–3293233	47-89984T4	Serial number range
135 HP V	135	2-Stroke	904646-UP	47-89984T4	Serial number range
140 HP	140	2-Stroke	3293234-UP	47-89984T4	Serial number range
140 HP JET	140	2-Stroke	D082000-UP	47-89984T4	Serial number range
150 HP	150	2-Stroke	3502806–4868647	47-89984T4	Serial number range
150 HP	150	2-Stroke	ALL	47-89984T4	Confirmed for all serial numbers
175 HP	175	2-Stroke	ALL	47-89984T4	Confirmed for all serial numbers
200 HP	200	2-Stroke	ALL	47-89984T4	Confirmed for all serial numbers
220 HP	220	2-Stroke	ALL	47-89984T4	Confirmed for all serial numbers
225 HP	225	2-Stroke	ALL	47-89984T4	Confirmed for all serial numbers
200 XS DFI (2.5L)	200	2-Stroke	0T235000–1E002110	47-89984T4	Mercury Racing model
200 XS DFI (2.5L) ROS	200	2-Stroke	1E050852 & Up	47-89984T4	Mercury Racing model
200 XS SST	200	2-Stroke	1E050629 & Up	47-89984T4	Mercury Racing model
200 EFI PRO MAX/SUPER MAG	200	2-Stroke	0G857000–0G858150	47-89984T4	Mercury Racing model
225 EFI PRO MAX/SUPER MAG	225	2-Stroke	0G857000–0T429939	47-89984T4	Mercury Racing model
225X EFI PROMAX	225	2-Stroke	0T430254–0T819605	47-89984T4	Mercury Racing model

Also compatible with Mercruiser sterndrive models, including Alpha One (Gen 1) and various high-performance/racing units.

Model	Type	Years	Serial Number Range	OEM Part No.	Notes
MC-I	Sterndrive	1980s	249518 & Later	47-89984T4
R/MR/ALPHA ONE	Sterndrive	1983–1990	6854393–0D469858	47-89984T4
R/MR/ALPHA ONE	Transom Assembly	1983–1990	6216687–0F386995	47-89984T4
FORMULA I (2 LITRE EFI)	High Performance	1986–1989	0A953232–0A953245	47-89984T4	Alpha 1 SS variant
S2000	Racing	1990s	0D030200 & Up	47-89984T4
SST 120	Racing	1990s	0D030200 & Up	47-89984T4

Technical Specs

Product Type: Water Pump Impeller
Installation: Direct fit - internal installation
Material: Neoprene rubber with metal alloy hub
Blades: 6
Dimensions: Height: 33.8 mm (1.33 in), Diameter: 60.0 mm (2.36 in), Hub Shaft Diameter: 22.2 mm (0.87 in)
Weight: 0.10 kg (3.5 oz)
OEM Reference: 47-89984T4
Color: Black rubber with brass/bronze hub
Warranty: Aftermarket: Varies by manufacturer

What’s in the Box

1 x Water Pump Impeller (47-89984T4)

Installation Notes

Disconnect the battery to prevent accidental starting.
Place the outboard motor or sterndrive in the tilted position and drain the gearcase oil.
Remove the lower unit (gearcase) by unbolting it from the engine's midsection.
Locate and unbolt the water pump housing cover to access the old impeller.
Remove the old impeller, noting the rotational direction of the blades. Clean any debris from the housing.
Lightly lubricate the new impeller and housing with a marine-safe lubricant.
Install the new impeller, ensuring the blades are oriented in the correct rotational direction.
Reinstall the water pump housing, using new gaskets if required, and torque bolts to manufacturer specifications.
Reattach the lower unit to the engine and refill the gearcase oil.
Reconnect the battery and test the engine using a water supply (flushing muffs) to verify proper water flow.

Troubleshooting & FAQ

How do I confirm this impeller fits my specific engine?

The most reliable method is to match your engine's model and serial number to the ranges listed in the compatibility tables. If you are unsure, check your engine's service manual or contact a qualified marine mechanic.

What is the recommended replacement interval?

For preventative maintenance, it's best practice to replace the water pump impeller every 100 operating hours or annually, whichever comes first. This can vary based on usage conditions (e.g., saltwater vs. freshwater).

What are the signs of a failing water pump impeller?

Common symptoms include a weak or non-existent water stream from the "telltale" outlet, engine overheating alarms, and in severe cases, steam from the exhaust. Reduced engine performance can also be a sign.

Should I lubricate the impeller during installation?

Yes, applying a light coat of 2-4-C marine grease or even dish soap to the inside of the pump housing and the impeller blades will ease installation and prevent damage during the first dry start.

Why is the number of blades important?

The number of blades (in this case, six) is engineered for a specific pump housing volume and flow rate. Using an impeller with a different blade count will result in incorrect cooling pressure and potential engine damage.

My sterndrive is an Alpha One Gen 2. Will this fit?

No, this impeller is specified for the Alpha One (Gen 1) sterndrives from 1983–1990. The Gen 2 models use a different water pump assembly and require a different impeller.

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.

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.