Sierra 18-30585

Upgrade Your OMC Water Pump with Reliable Performance

Keep your outboard or stern drive running cool and efficient with this precision-engineered impeller designed as a direct replacement for OMC part 3854072. Crafted by Sierra Engine Parts, this component tackles the heart of your water pump system, ensuring consistent water flow to prevent overheating during long days on the water. Boat enthusiasts know that a worn impeller can lead to costly engine damage, but swapping in this durable piece restores factory-level reliability without the hassle of original equipment markups.

Perfect Fit for OMC Engines

This impeller slots seamlessly into a wide range of OMC models, matching the exact specifications of the genuine 3854072. Whether you're maintaining a classic Johnson or Evinrude, it delivers the torque and flexibility needed for optimal pump operation. Boaters often search for cross-compatible parts like this to keep legacy engines alive, and Sierra's engineering ensures it performs under high-RPM demands typical of inboard/outboard setups.

• Direct replacement for OMC 3854072
• Compatible with various OMC inline and V-engine water pumps
• Meets or exceeds OEM tolerances for vane geometry and hub design

Built Tough for Marine Conditions

Marine environments are brutal—saltwater corrosion, debris ingestion, and heat cycles chew through lesser parts. Sierra counters this with high-grade neoprene construction that resists swelling, cracking, and dry rot far better than bargain alternatives. The flexible vanes hug the pump housing for maximum water pickup, even in shallow drafts or weedy waters, extending service life and reducing maintenance frequency.

Real-world feedback from seasoned captains highlights its edge: it grips tighter during startup, pumps stronger after winter storage, and holds up through thousands of hours. Skip the guesswork; this isn't just a part—it's insurance against roadside (or waterside) breakdowns.

Effortless Installation Tips for DIY Mechanics

Replacing your impeller shouldn't turn into a full-day ordeal. Start by draining the pump and noting the rotation direction—OMC pumps typically spin clockwise from the drive side. Use a gentle lubricant like soapy water (never petroleum-based) to ease insertion, twisting gently while aligning splines. Pro tip: inspect the wear plate and housing for scoring; a quick sand with fine emery cloth can extend the life of the entire assembly.

A common pitfall? Forcing it in dry, which distorts vanes and kills flow. With basic tools—a flathead screwdriver, puller if needed, and 15 minutes—you're back fishing. Always prime the system post-install by running in a barrel or on muffs to burp air pockets.

Spot Trouble Early: Signs Your Impeller Needs Replacing

Don't wait for steam rising from the cowling. Watch for these red flags:

• Overheating gauge spikes, especially at idle or trolling
• Reduced pee stream from the tell-tale outlet
• Bits of rubber in the pump strainer or cooling water
• Engine bogging under load from vapor lock

Annual checks are smart, but if your boat sits unused, inspect every six months. Heat and age are silent killers—proactive swaps like this Sierra unit keep adventures uninterrupted.

Frequently Asked Questions