Sierra 18-3091 Impeller Assembly - Marine Water Pump Impeller

The Sierra 18-3091 Impeller Assembly is a replacement impeller built for the raw water pump on marine engines, the component responsible for pulling in outside water to cool the engine while it runs. As the impeller wears, spins, or loses vanes, cooling flow drops and the engine can run hot; swapping in a fresh Sierra 18-3091 restores that water flow and protects the pump housing and engine from heat damage. Sierra engineers its water pump parts to meet or exceed the performance of the original equipment part being replaced, and the company supplies impellers and pump components to OEM engine manufacturers and boat builders, so the fit and finish match what came off the engine originally.

The 18-3091 measures 1.6 x 1.6 x 1 inches and weighs 0.06 pounds, a compact size consistent with a small-engine or outboard raw water pump impeller. It has a white, powder-coated finish. Keeping a spare on hand is good practice for any boat owner who services their own cooling system, since impellers are considered routine wear items and are typically checked or replaced on a seasonal basis.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-3091
• Product Type: Impeller Assembly
• UPC: 808282258702
• Color: White
• Finish: Powder Coated
• Item Dimensions: 1.6 x 1.6 x 1 inches
• Weight: 0.06 pounds
• Unit Count: 1 count

Frequently Asked Questions

What is the Sierra 18-3091? It is an impeller assembly for a marine raw water pump, part number 18-3091, sold by Sierra.

What are the dimensions of the 18-3091 impeller? The Sierra 18-3091 measures 1.6 x 1.6 x 1 inches.

How much does the 18-3091 impeller weigh? 0.06 pounds, which is the shipping and product weight for the Sierra 18-3091 impeller assembly.

What color and finish does the 18-3091 impeller have? White, with a powder-coated finish.

How many impellers come in one order of 18-3091? One count; the Sierra 18-3091 is sold as a single impeller assembly.

Is the Sierra 18-3091 an OEM part or aftermarket? The 18-3091 is a Sierra-brand replacement part engineered to meet or exceed the original equipment part it replaces, rather than an OEM-branded part.

What is the UPC for the Sierra 18-3091 impeller? 808282258702 is the UPC associated with the Sierra 18-3091 impeller assembly.

Why does a raw water pump impeller need to be replaced? Impellers wear down, lose vanes, or take a set over time, which reduces the water flow the pump draws in to cool the engine; the Sierra 18-3091 is a direct replacement impeller assembly to restore that flow.

Does Sierra make its own water pump parts or resell OEM stock? Sierra manufactures its own line of marine parts, including the 18-3091 impeller assembly, and also supplies parts to OEM engine manufacturers and boat builders.

Is the 18-3091 impeller a wear item that should be replaced on a schedule? Yes, impellers such as the Sierra 18-3091 are a routine wear component in a raw water pump and are commonly inspected or replaced on a seasonal basis.