Overview

The Jabsco 18948-0001-P is a replacement impeller kit for flexible impeller pumps used for engine cooling water, bilge, transfer, and other general-purpose marine pump duties. It uses a 12-blade neoprene impeller with a key-drive hub, a 2-9/16 in diameter, a 1-5/8 in width, a 5/8 in shaft diameter, and a brass insert, so the fit needs to match the pump and the impeller you are taking out.

On a boat, this is the kind of service part that matters most when raw-water flow starts to drop or when you are doing scheduled maintenance before the season. Neoprene suits engine cooling and general water-handling duties, and the keyed drive matters because it locks the impeller to the shaft rather than relying on friction alone.

For buyers replacing an existing impeller, the safest check is to match the blade count, outside diameter, width, shaft size, and drive style to the old part and pump model before ordering. Keeping a spare on board also makes sense for boats that run long distances, fish offshore, or depend on an engine cooling pump away from the dock.

Key features

• 12-blade neoprene impeller for raw-water engine cooling and other flexible impeller pump service where neoprene is the correct material
• Key-drive hub, which matters for pumps that require a keyed shaft connection
• 2-9/16 in outside diameter, 1-5/8 in width, and 5/8 in shaft diameter for fit checks before installation
• Brass insert in the hub
• Works as a replacement service part for many bronze flexible impeller pumps used on boats
• Useful as both planned maintenance stock and an onboard spare for emergency impeller changes

Compatibility and fit

This kit is a fit-driven purchase, not a universal impeller. Before installing it, compare the dimensions and the keyed hub to your current impeller, and confirm the pump is set up for a 12-blade neoprene impeller in this size. That matters more than brand names on the pump body, especially on older boats where pumps may have been changed at some point in the boat's life.

It is a practical match for owners servicing raw-water cooling pumps on inboard engines and for anyone maintaining flexible impeller pumps used for bilge, transfer, or general water movement where this size and material are specified. The right buyer is someone replacing the same impeller pattern already in service and wanting to restore pump output without changing the pump itself.

Installation and service

When changing an impeller, remove the end cover and pull the old impeller from the hub rather than prying against the pump body. Greasing the new impeller before installation helps it slide into the bore and gives added protection during the first prime. Once the cover seal is back in place and the cover is reinstalled, the pump is ready to go back into service.

Flexible impellers are wear items, so regular inspection is worth doing on any boat that sees heat, sand, silt, dry starts, or long engine hours. Replacing them on a schedule is usually easier than dealing with a loss of cooling water flow underway.