Sierra 18-3239 Impeller Repair Kit for Mercury/Mariner Outboard, Replaces 47-89981

The Sierra 18-3239 Impeller Repair Kit is a complete water pump rebuild kit for Mercury/Mariner outboard motors. It bundles the three components needed to restore proper cooling system operation in one purchase: a replacement impeller, an impeller plate, and an O-ring, so the water pump housing can be rebuilt without hunting down individual parts separately. Keeping the water pump impeller in good condition is essential to outboard engine health, since a worn or cracked impeller reduces raw water flow to the engine and can lead to overheating. This kit is built to the fit and function of the original equipment parts it replaces, using materials designed to hold up in continuous exposure to saltwater and freshwater marine environments. The kit is intended for Mercury/Mariner outboard engines and is a straightforward drop-in replacement during routine water pump service or when rebuilding a water pump housing. Sierra manufactures marine parts to OEM specifications and supplies engine manufacturers and boat builders with replacement components, so this kit is engineered to meet or exceed the performance of the original Mercury/Mariner parts it replaces.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-3239
• Product Name: Impeller Repair Kit
• Category: Mercury Outboard Water Pumps and Impellers
• Kit Contents: Sierra 18-3039 Impeller, Sierra 18-3139 Impeller Plate, Sierra 18-7409 O-Ring
• Unit Count: 1 kit
• Weight: 0.06 pounds
• UPC: 030999236906

Fitment

• Mercury/Mariner outboard motors

Replaces (OEM)

• 47-89981 (impeller)
• 46895 (impeller plate)

Frequently Asked Questions

What does the Sierra 18-3239 Impeller Repair Kit include? The kit contains one Sierra 18-3039 impeller, one Sierra 18-3139 impeller plate, and one Sierra 18-7409 O-ring, giving you everything needed to rebuild the water pump housing in one purchase.

Which engines does the 18-3239 kit fit? This impeller repair kit is designed for Mercury/Mariner outboard motors.

What OEM part numbers does the Sierra 18-3239 kit replace? The impeller in this kit replaces OEM number 47-89981, and the impeller plate replaces OEM number 46895.

Is the impeller sold separately from the plate and O-ring? No, the Sierra 18-3239 is packaged as a complete kit with the impeller, impeller plate, and O-ring included together rather than sold individually.

How much does the 18-3239 Impeller Repair Kit weigh? The kit weighs 0.06 pounds.

Is this a genuine Sierra part or an aftermarket copy? The 18-3239 kit is a genuine Sierra manufactured product, built to meet or exceed the specifications of the original equipment parts it replaces.

Do I need any other parts to rebuild my water pump with this kit? The 18-3239 kit supplies the impeller, impeller plate, and O-ring; depending on the condition of your water pump housing, you may still need a separate housing or gasket set if those components are worn.

What is the UPC for the Sierra 18-3239 kit? The UPC for the Sierra 18-3239 Impeller Repair Kit is 030999236906.

Why does the water pump impeller need periodic replacement? The impeller in a Mercury/Mariner outboard water pump wears down over time and can crack or lose its vanes, which reduces cooling water flow and risks engine overheating; the 18-3239 kit provides the parts to replace it.

Can this kit be used on both Mercury and Mariner outboards? Yes, the Sierra 18-3239 Impeller Repair Kit is designed for use on Mercury and Mariner outboard motors.