Mercury – Carburetor Diaphragm Kit for 30–65hp 2-Stroke Outboards | Fuel System Rebuild Kit | Precision Marine Components | 857005A1

Overview

There’s something deeply reassuring about knowing your outboard will respond the moment you nudge the throttle. No hesitation, no stumbling—just that smooth surge you feel in your hands and hear in the engine’s tone. When a carburetor starts to wear, you can sense the difference long before you see it. That’s why the Mercury Marine part number 857005A1 Carburetor Diaphragm Kit is such a valuable piece of the puzzle. It brings back that crisp, lively fuel delivery that makes a two-stroke feel young again, giving you a sense of reliability you can take out on the water without second-guessing.

Key Features

• Twelve-piece kit designed to restore proper carburetor diaphragm performance
• Includes fuel pump diaphragms, gaskets, check valves, spring, cap, and screws
• Manufactured from durable marine-grade materials for long-term stability
• Built to Mercury Marine OEM specifications for exact fit and consistent operation
• Helps correct rough running, hard starts, and inconsistent fuel delivery

Engine & Boat Compatibility

• Fits select Mercury and Mariner 30–65 horsepower 2-stroke outboards
• Works with models that utilize diaphragm-style carburetors
• Ideal for fishing boats, aluminum skiffs, inflatables, small pontoons, and utility craft
• Suitable for owners wanting OEM reliability without modifying fuel components

Performance & Practical Benefits

A well-rebuilt carburetor changes the entire feel of an outboard. With the 857005A1 kit installed, the fuel system breathes with a smooth, steady rhythm again. Starts come easier. Idle settles into a tight, predictable purr. When you roll into the throttle, the engine responds cleanly instead of coughing or lagging. It’s the kind of improvement you can literally feel in the way the boat moves across the water.

Each component in this kit is engineered to handle the realities of marine use—constant vibration, temperature swings, and the moisture that inevitably finds its way inside the cowling. The diaphragms flex exactly the way they should, while the gaskets and check valves seal securely to eliminate fuel leaks and low-pressure hiccups. Installation is straightforward for anyone familiar with carburetor service, and the fitment is clean thanks to Mercury’s precise engineering. No trimming, no improvising—everything sits exactly where it’s supposed to.

The result is a more responsive engine, better fuel consistency, and fewer frustrations when maneuvering in tight spaces or running long distances. It’s one of those maintenance steps that pays for itself in smoother operation, better starts, and peace of mind on every trip.

Why Buy OEM

When it comes to carburetor internals, there’s no room for guesswork. Mercury Marine OEM parts are built with exact material tolerances and engineered to withstand the chemical and mechanical stress of daily boating. Aftermarket kits may look similar, but the diaphragm thickness, spring tension, and gasket density often fall short—leading to uneven fuel delivery or early failure. With the 857005A1 kit, you know you’re getting components designed for your specific outboard, tested under real-world marine conditions, and built to last. It’s a smart, practical choice for any boater who values dependable performance.

FAQ

Q1: Which engines does the Mercury 857005A1 Carburetor Diaphragm Kit fit?

It fits select Mercury and Mariner 30–65 horsepower 2-stroke outboards that use diaphragm-style carburetors.

Q2: What makes this kit better than aftermarket alternatives?

The materials, fitment, and engineering match Mercury’s exact OEM specifications, ensuring consistent fuel delivery and long-term reliability.

Q3: How do I know if this is the correct replacement for my setup?

Check your owner’s or service manual for part number 857005A1 or compare with your existing components.

Q4: Can this kit be used in both freshwater and saltwater applications?

Yes, the marine-grade materials are designed to perform well in both environments.

Q5: Is installation straightforward?

Most boaters familiar with carburetor service find it simple thanks to the precise OEM fit and complete kit components.