Mercury – Water Pump Housing | OEM Replacement for 25 & 30HP FourStroke Outboards | 803750T05

Overview

If your engine isn’t staying as cool as it used to, it might be time to replace the water pump housing — the heart of your cooling system. The Mercury Marine 803750T05 Water Pump Housing is built tough for 25HP and 30HP FourStroke outboards, giving you factory-quality performance and peace of mind. It’s made from durable, marine-grade materials that hold up to years of heat, vibration, and water exposure. When installed, it restores proper water flow and seals your system the way Mercury intended — no leaks, no guesswork, just reliable cooling every time you start the motor.

Key Features

• Purpose: Replaces a worn or cracked housing to restore proper water circulation.
• Construction: Built from marine-grade material tested for strength and corrosion resistance.
• Design: OEM precision molding ensures a snug, watertight seal and dependable cooling.
• Durability: Withstands high heat and pressure in both saltwater and freshwater.
• Ease of Use: Fits cleanly into place with no modifications — just bolt it on and go.

Engine & Boat Compatibility

• Mercury 25HP carbureted FourStroke outboards
• Mercury 3-cylinder 25HP and 30HP EFI FourStroke outboards

Performance & Real-World Benefits

The 803750T05 water pump housing keeps your cooling system working the way it should. When the old housing wears down, it can cause leaks or reduce water pressure — and that’s when overheating starts. This replacement part brings back the smooth water flow your engine depends on to stay cool and protected.

It’s made for the realities of boating life — long days on the water, salt exposure, and constant heat cycling. Once installed, it fits tight, seals properly, and keeps water moving efficiently so your outboard stays in its comfort zone.

Why Choose Mercury OEM

The Mercury 803750T05 is a genuine factory part, designed specifically for your outboard. Cheaper replacements might save a few dollars upfront but often use softer plastics that warp or crack under heat and pressure.

Mercury’s OEM housing is built from tougher material and tested to handle real marine conditions. It’s the same part Mercury technicians use in their service shops — proven to last and guaranteed to fit right the first time.

FAQ

Q1: What does this part include?
You’ll receive the water pump housing only, ready for installation.

Q2: Why should I replace it?
If your housing is worn or damaged, it can lead to leaks, low pressure, or overheating.

Q3: How durable is it?
It’s made from high-strength, corrosion-resistant material built for long-term use in harsh marine environments.

Q4: Is it easy to install?
Yes — it’s a direct OEM fit that installs easily using standard tools.

Q5: Why go OEM instead of aftermarket?
OEM parts are built to Mercury’s exact standards, meaning better materials, better fit, and better longevity on the water.