Sierra 18-3016-1 Mercury/Mariner Impeller Repair Kit

Keep your Mercury or Mariner outboard running cool and reliable with the Sierra 18-3016-1 Impeller Repair Kit. Boat owners know the frustration of a failing water pump impeller—sudden overheating, steam billowing from the engine cowling, and a day on the water cut short. This kit steps in as your go-to solution, packing all the essentials to restore proper cooling flow without the hassle of sourcing parts separately.

Why Your Outboard Needs This Impeller Repair Kit

Impellers wear out from constant exposure to sand, debris, and dry running during trailering or storage. A damaged impeller starves the engine of cooling water, risking costly repairs. Unlike stock parts that might leave you waiting, this Sierra kit delivers durable neoprene construction that flexes under heat and pressure, gripping the pump shaft securely for years of service. It's designed for the real-world demands of saltwater fishing trips, family outings, or competitive boating.

What's Included in the Kit

• High-quality neoprene impeller for optimal water flow and longevity
• Key for easy pump disassembly
• Inspect/replace gasket to prevent leaks
• Face plate O-ring for a tight seal
• Drive key to ensure positive engagement
• Copper tube for flushing out old debris
• Thorough cleaning brush to prep surfaces
• Anti-seize lubricant for smooth installation

Every component is precision-engineered to match OEM specs, ensuring a perfect fit and performance that keeps your engine temps steady even on hot summer days.

Perfect Fit for Mercury and Mariner Models

This kit covers a wide range of 4 to 225 HP Mercury/Mariner engines from 1963 to 1984, including popular 65, 75, 90, 115, 125, and 140 HP models. Always cross-reference your engine's serial number for exact compatibility, but it's a staple for many classic two-stroke powerheads. Whether you're maintaining a vintage kicker or a workhorse kicker, it slots right in.

Step-by-Step Installation Guide

Replacing the impeller is a straightforward DIY job that takes under an hour with basic tools. Here's how to do it right:

1. Drain the water from the pump housing and remove the lower unit if needed.
2. Use the included key to twist off the pump housing—twist counterclockwise while supporting the shaft.
3. Flush debris with the copper tube and brush, then inspect the cam for wear.
4. Lubricate the new impeller with anti-seize, align the vanes outward, and slide it onto the shaft.
5. Reinstall the drive key, O-ring, face plate, and gasket. Torque to spec (usually 75-95 in/lbs).
6. Test flush on muffs before hitting the water—watch for strong tell-tale flow.

Pro tip: Replace every two years or 200 hours to stay ahead of failures. If you're new to this, grab a service manual for your model to double-check torque values.

Benefits That Outlast the Competition

Sierra's reputation shines through in this kit's robust materials and complete contents—no hunting for missing O-rings at the last minute. It saves you downtime, protects your investment, and delivers peace of mind on the water. Anglers report cooler running temps post-install, and mechanics praise the ease of service. It's not just a repair; it's proactive maintenance that extends engine life.

Maintenance Tips for Long-Lasting Performance

To maximize the kit's lifespan:

• Flush your engine after every saltwater use to rinse salt buildup.
• Never run dry—tilt up promptly when beaching.
• Store with ears down or fog the engine to keep the impeller lubed.
• Check tell-tale stream pressure annually; weak flow signals trouble.
• Pair with a fresh water pump rebuild if your cam is scored.

These habits turn a simple kit into your engine's best defense against overheating woes.