Water Pump Repair Kit – Fits Mercury/Mariner 9.9-15 HP 4-Stroke Outboards (Replaces 99157T2)

Product Details

This Water Pump Repair Kit – Fits Mercury/Mariner 9.9-15 HP 4-Stroke Outboards (Replaces 99157T2) is a complete aftermarket solution designed for a range of Mercury and Mariner outboard engines. It is engineered to fit 9.9 HP 4-stroke (323cc) BigFoot models (USA-made serial numbers 0G760300–0T979999 and Belgium-assembled 0P075166–0P325499), and 15 HP BigFoot 4-stroke outboards (USA-made serial numbers 0G590000–1B727495 and Belgium-assembled 997311 and up).

This kit serves as a direct replacement for Mercury/Mariner part numbers 99157T2, 99157A2, 99157A02, 46-99157T2, 46-99157A02, and 85098A2.

• Installation Method: Installs as a direct replacement for the original pump assembly.
• Performance: Designed to deliver higher flow rates for enhanced engine cooling.
• Complete Kit: Includes the impeller, housing, gaskets, and seals required for a full service.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For Mercury and Mariner outboards, it is critical to verify your engine's serial number against the ranges provided to ensure an exact match.

Technical Specs

Product Type

Water Pump Repair Kit

Installation

Direct replacement

Technical Attributes

Designed for higher flow rates and cooling flow

What’s in the Box

• 1 x Pump Housing Assembly (Replaces 99157A02/99157A1)
• 1 x Face Plate (Replaces 85083)
• 1 x Gasket (Replaces 993261)
• 1 x Water Pump Impeller (Replaces 8508910/47-85089-3/47-85089-10)
• 1 x Key (Replaces 8M0032838)
• 1 x Seal (Replaces 85090001/85090)
• 2 x Washer (transparent)
• 4 x Grommet
• 6 x O-ring (includes sizes 69202, 35276, 86203)

Installation Notes

1. Disconnect the spark plug wires and battery for safety.
2. Place a drain pan beneath the lower unit and remove the drain/fill screws to empty the gearcase oil.
3. Remove the bolts that secure the lower unit (gearcase) to the engine's upper section.
4. Carefully lower and separate the gearcase from the driveshaft housing. The driveshaft remains with the gearcase.
5. Unbolt and remove the old water pump housing to expose the impeller. Note the orientation of the old parts.
6. Remove the old impeller, key, gaskets, and wear plate. Thoroughly clean all mating surfaces.
7. Install the new wear plate, gaskets, and seals as provided in the kit.
8. Install the new key and slide the new impeller onto the driveshaft. Rotate the shaft clockwise to help seat the impeller vanes correctly inside the housing.
9. Secure the new pump housing with its bolts, tightening them to the manufacturer-specified torque.
10. Reinstall the lower unit, ensuring the driveshaft, shift shaft, and water tube are properly aligned.
11. Refill the gearcase with new marine-grade gear oil until it flows from the upper vent hole.
12. Reconnect the battery and test the engine in water, confirming a strong, steady stream from the tell-tale outlet.

Troubleshooting & FAQ

Safety & Important Info

• Verify images and specifications against your original part before purchase. If anything differs—even if your model is listed as compatible—do not order.
• This is an aftermarket replacement part, not an original equipment manufacturer (OEM) component.
• Professional installation is highly recommended for safety, proper function, and to prevent engine damage.

About Sea Sierra

• Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and rigorously tested for demanding real-world conditions.
• Fast Global Fulfillment — We offer free standard delivery to most regions with an average transit time of 5–15 days.
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