SKU: 98425885831

Water Pump Impeller Kit for Yamaha 25HP-40HP Outboards

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Description

Water Pump Impeller Kit for Yamaha 25HP-40HP OutboardsWater Pump Impeller Kit Fits Yamaha 25HP 40HP Outboards (Replaces 66T W0078 A0) This water pump impeller service kit is designed for Yamaha 2 stroke and 4 stroke outboard engines ranging from 25HP to 40HP, covering models from approximately 1993 to 2006. It provides the essential components needed to restore the performance of your engine's cooling system. This kit is a direct replacement for Yamaha OEM part numbers, including 66T W0078 A0, 66T W0078

Water Pump Impeller Kit – Fits Yamaha 25HP-40HP Outboards (Replaces 66T-W0078-A0)

This water pump impeller service kit is designed for Yamaha 2-stroke and 4-stroke outboard engines ranging from 25HP to 40HP, covering models from approximately 1993 to 2006. It provides the essential components needed to restore the performance of your engine's cooling system.

This kit is a direct replacement for Yamaha OEM part numbers, including 66T-W0078-A0, 66T-W0078-A0-00, 66T-W0078-00-00, and 66T-W0078-01-00. It also cross-references with Sierra 18-3432 and GLM 89890.

  • Engineered as a direct-fit replacement for straightforward installation.
  • Restores cooling efficiency to prevent engine overheating.
  • Includes all essential components for a standard water pump service.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Brand Part Number Notes
Yamaha 66T-W0078-A0 Primary replacement
Yamaha 66T-W0078-A0-00
Yamaha 66T-W0078-00-00
Yamaha 66T-W0078-01-00
Yamaha 61N-W0078-11-00 Alternative kit for C30 models
Sierra 18-3432 Aftermarket equivalent
GLM 89890 Aftermarket equivalent

Compatible Engine Models

Confirm your engine model/year in the table below. For Yamaha owners, here’s a guide to help you identify your engine’s serial/model: Yamaha Serial Number Guide. You can also review exploded diagrams to verify part numbers: Yamaha Parts Diagrams & Catalog.

Brand Model Rated HP Stroke Years OEM Part No. Notes
Yamaha F25 25 4-Stroke 1998-2006 66T-W0078-A0
Yamaha F30 30 4-Stroke 2001-2006 66T-W0078-A0
Yamaha F40 40 4-Stroke 1999-2006 66T-W0078-A0
Yamaha C30 30 2-Stroke 1993-1997 61N-W0078-11-00 Alternative kit

Technical Specifications

Specification Value
Product Type Water Pump Impeller Kit
Installation Direct replacement

Package Contents

  • 1 x Impeller
  • 1 x Water Pump Housing Gasket
  • 1 x Wear Plate to Gear Case Mounting Gasket
  • 1 x Wear Plate to Pump Housing Gasket
  • 1 x Impeller Key
  • Additional gaskets and O-rings may be included depending on specific kit configuration.

Installation Guide

  1. Safety First: Disconnect the battery and remove the propeller before starting.
  2. Access the Lower Unit: Drain the gearcase oil. Then, unbolt and carefully remove the lower unit (gearcase) from the outboard motor.
  3. Remove Pump Housing: Locate the water pump assembly on top of the gearcase. Remove the bolts securing the water pump housing.
  4. Inspect and Replace Impeller: Lift off the housing and slide the old impeller off the driveshaft. Note the direction of the old impeller's vanes.
  5. Replace Components: Clean all surfaces. Install the new gaskets, wear plate, and impeller key. Slide the new impeller onto the shaft, rotating it in the correct direction to seat the vanes.
  6. Reassemble: Reinstall the pump housing, ensuring a proper seal. Reattach the lower unit to the engine, refill the gearcase oil, and reconnect the battery.
  7. Test Operation: Start the engine in water and verify a strong, steady stream of water from the tell-tale outlet.

Troubleshooting & FAQ

How do I confirm this kit fits my engine?
First, check your engine's model, horsepower, and year against our compatibility table. Second, verify that your existing part number matches one of the OEM or aftermarket numbers listed in the cross-reference section. This ensures the most accurate fit.

What are the signs of a failing water pump impeller?
Common symptoms include an engine that is overheating, a weak or intermittent water stream from the tell-tale (water indicator), or visible damage like cracked or missing vanes on the old impeller upon inspection.

How often should I replace the water pump impeller?
For preventative maintenance, we recommend inspecting the impeller annually and replacing it every 1 to 2 years (or 100-200 hours). Replacement frequency may depend on usage, water conditions (saltwater vs. freshwater), and storage.

Is this an OEM part?
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.

How fast do you ship and how much does it cost?
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.

What is your warranty and return policy?
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?

  • Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
  • Fast Global Shipping: Free delivery worldwide in 5–15 days.
  • Direct from Manufacturer: Competitive pricing without compromising quality.
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 98425885831

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4.5 ★★★★★
Based on 9 reviews
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ralversity
Bozeman, US
★★★★★ 3
Does the job, but assembling by yourself is a nightmare
Size: 4 Panel-88'', Color: Black
Does it do the job? Yes, although as others said there are small gaps but it's not a huge deal. The price is also good. But the reason I'm giving it a 3/5 is simply because the assembly for this was a complete nightmare. I honestly don't think I would recommend this to anyone unless they have another person to help them assemble it, because doing it by myself was terrible. I don't think I'd buy this again, I think I'd opt to just spend a bit more money and save myself the trouble personally.
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Reviewed in the United States on May 29, 2026
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Verified Purchase
Talagand
Charlottesville, US
★★★★★ 4
Reasonably adequate room divider
Size: 4 Panel-88'', Color: Beige
I'm reviewing this as I assemble it. Couple things: 1. I didn't expect as much assembly. I've ordered dividers before and they more-or-less came as one unit. Sometimes the panels needed screwing together. These require complete assembly and come largely as three rods: two make up vertical columns and snap together. Another one (called part "C") makes the horizontal columns and you have two of these per panel (one attaches to part "A" and the other part "B"). These parts are metal with a plastic shim. Using the wood screws to attach to part "C" is a real pain in the neck. There's not much holding the panel in place so it's a little tricky. One tactic I've found while I'm assembling that works for the initial connections from parts A and B to their respective "C" rods is to hold the screw in place with a screw driver and then rotating the rod around the screw. This will do a number on your hands if you aren't wearing gloves. This obviously doesn't work when completing the connection. Using a driller driver on this is really near impossible because there isn't anything you can use to secure it in place. You can use it on the first panel, but as it gets longer, it becomes increasingly difficult and because it isn't wood, it's really tight. I considered drilling larger pilot holes but since there are only 4x4=16 screws I need to screw in, I just decided to use my screw driver to complete it. 2. Also related to assembly. When completing the panels (attaching parts "A" and "B" to parts "C" that have the cloth cover on it), you have to be careful that when you tighten that side that it isn't loosening the other side. Because the pilot holes are so tight, you can end up rotating the rod, which rotates it in the same direction as looser on the original side. Having someone hold the "C" rod in place while you screw it in is probably the easiest approach. I didn't have a 2nd person, so I just had to keep flipping back and forth and tightening both sides as I screwed it in. Not the worlds biggest deal, but annoying nonetheless. 3. The way the instructions are written, they seem to suggest building this thing progressively; that is, you do panel 1, then 2, connect them together, then do 3 and connect it, etc. I took a different route that I suspect saved me quite a bit of trouble, and I assembled all four panels first and THEN connected everything together. 4. For the love of God make sure you check that the plastic tip is on the same side for every panel. Otherwise, you have to take one side apart again and reverse it. On the bright side, if this happens, you've essentially bored out the pilot holes to be the correct size... which is having me question if I shouldn't have just bored them out to the appropriate width in the first place. 5. Attaching all of the panels together is also an enormous pain in the ass unless you happen to have an 88" long elevated surface. Attaching the legs either requires you to elevate one side, which will invariably twist the inexplicably cheap material in the bottom connectors... or you can attach them sideways... or you can put this thing upright, having two people hold the panels in place while you use the allen wrench to tighten the bolts on the underside. None of those are particularly great options. NOW on to the utility itself. 1. The panels do let some light through (I didn't believe their advertising, and that was one of the reasons that I bought beige, is that I wanted it to not be too dark). They aren't transparent though, so it isn't that far off from their description. They functionally work great, and keep the mess of wires hidden and when I'm sitting at my desk, actually reflect quite a bit of light into my office. Great! 2. My wife has described these as "the most hideous piece of furniture ever conceived of by man." So it does not have spouse approval factor. Granted, she will seldom be in my office area, so that isn't the end of the world. 3. These are really hard to align in a way that doesn't look a little tacky. There are some plastic connectors but they don't do a bang up job of keeping these in place. Each panel is slightly tilted and it's... quite obvious. I may at some point make my own improvements to these to help make them more level. It's not a particularly expensive product so I wasn't expecting much so it's fine and I'm not going to ding them on the rating because of it. All said, would I buy this product again? Probably not. It's assembly was ~90 minutes which is about 75 minutes longer than I was anticipating spending on this (not including the 5 minute writeup that I'm doing here). But am I going to return it? Also no, if for no other reason I'd be just as annoyed taking it apart and putting it in the original box to return it.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on October 31, 2023
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Verified Purchase
Val
Chelsea, US
★★★★★ 5
True to Description
Color: Black, Size: 4 Panel
Love it!! I bought it for privacy while the nurse is dressing my dad. There were several colors black matched the decor . It blocked the sunlight and street lights. Durability and quality very good. Easy closure when not in use. Lightweight. No assembly needed
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Reviewed in the United States on May 29, 2026
C
Verified Purchase
Clockworks
Whiting, US
★★★★★ 5
Nice room divider!
Color: White, Size: 8 Panel
The white panels are a nice off-white color. shipped in perfect condition. Already assembled so set up was quick. We use them to separate a photo studio from the main entry. Easily covers a 6 Ft. opening to the room. They are a woven material with wood colored sticks to support the weave. They are about 6 Ft. tall at the top of the curved section but less at the hinged sections. Light and easy to set up and take down. We are straddling two different floors so the extended legs at the bottom make this easy. Not sure how to clean them but they look great so far!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on October 21, 2025
R
Verified Purchase
Rockermom
Port Orchard, US
★★★★★ 5
Instant Privacy
Color: Beige, Size: 8 Panel
Bought this to separate a ground level living area used as an office. Works well to cover visual clutter; allows a clean look when entering the front door. Comes fully assembled. Hinges are sturdy enough, as long as the panels aren’t stretched too far; have to allow some bend between them. For the price point, quality and functionality are satisfactory.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on August 22, 2025

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