Water Pump Repair Kit Without Housing for Mercury Mariner 9.9–20 HP 4-Stroke EFI – Replaces 8M0135821 and 8M0137849
Water Pump Repair Kit Without Housing for Mercury Mariner 9.9–20 HP 4-Stroke EFI – Replaces 8M0135821 and 8M0137849 is backordered and will ship as soon as it is back in stock.
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Water Pump Repair Kit Without Housing for Mercury Mariner 9.9–20 HP...
Water Pump Repair Kit Without Housing for Mercury Mariner 9.9–20 HP 4-Stroke EFI – Replaces 8M0135821 and 8M0137849 is backordered and will ship as soon as it is back in stock.
Product Details
This Water Pump Repair Kit Without Housing is intended for specified Mercury and Mariner 4-stroke EFI outboards. The company catalog identifies the Mercury/Mariner application as a service kit supplied without the water-pump housing. It is designed for Mercury/Mariner 9.9 EFI models with serial numbers beginning at 1R00814 and 10, 15, and 20 EFI models with serial numbers beginning at 0R833820.
This is an aftermarket repair kit, not a complete water-pump housing assembly. Reuse the existing housing only if it is serviceable and compatible with the replacement components.
- Service-kit configuration for replacing worn water-pump components.
- Mercury/Mariner application coverage is defined by engine model and serial-number range.
- Housing is not included in the Mercury/Mariner configuration recorded for this product.
Part Number Matrix
Use the following manufacturer reference numbers to compare your original part and confirm application before ordering.
| Brand | Manufacturer Reference |
|---|---|
| Mercury Mariner | 8M0135821 |
| Mercury Mariner | 98-8M0135821 |
| Mercury Mariner | 90-8M0125267 |
| Mercury Mariner | 8M0137849 |
| Mercury Mariner | 46-8M0135821 |
| Tohatsu | 3RS-87322-1 |
| Tohatsu | 3RS-87322 |
Engine & Model Compatibility
Keep the horsepower, stroke, model family, and serial-number conditions together when checking fitment. The Mercury/Mariner applications below are the primary fitment recorded for the no-housing configuration.
| Brand | Model | Rated HP | Stroke | Serial Condition | Reference Numbers | Housing |
|---|---|---|---|---|---|---|
| Mercury/Mariner | 9.9 EFI | 9.9 | 4-Stroke | 1R00814 and above | 8M0135821, 98-8M0135821 | Not included |
| Mercury/Mariner | 10 EFI | 10 | 4-Stroke | 0R833820 and above | 8M0135821, 8M0137849 | Not included |
| Mercury/Mariner | 15 EFI | 15 | 4-Stroke | 0R833820 and above | 8M0135821, 8M0137849 | Not included |
| Mercury/Mariner | 20 EFI | 20 | 4-Stroke | 0R833820 and above | 8M0135821, 8M0137849 | Not included |
The company catalog also lists this product number for Nissan/Tohatsu MFS15E and MFS20E applications under separate service-kit records. Those records describe a housing-included configuration, so do not use the Mercury/Mariner no-housing contents for a Tohatsu order. Confirm the engine brand, model, stroke, original part number, and supplied-kit configuration before purchase.
Technical Specs
- Product Type
- Water pump repair/service kit
- Primary Application
- Mercury and Mariner 4-stroke EFI outboards
- Mercury/Mariner Configuration
- Service kit without water-pump housing
- Installation
- Replacement of compatible water-pump service components using the existing serviceable housing
- Fitment Reference
- Mercury/Mariner 9.9 EFI from 1R00814; 10, 15, and 20 EFI from 0R833820
What’s in the Box
The Mercury/Mariner catalog entry identifies this product as a water-pump service kit without the housing. The exact component list and quantities are not specified in the company record, so compare the supplied kit with the product images and your original parts before installation.
- Water-pump service components for the specified application
- Water-pump housing: not included for the Mercury/Mariner configuration
Do not assume that lubricant, bolts, a housing, or additional seals are included unless shown in the product package or confirmed for the applicable engine configuration.
Installation Notes
- Verify the engine brand, model, stroke, horsepower, serial number, and original water-pump reference number before beginning work.
- Disconnect the battery and place the outboard in neutral.
- Remove the lower unit according to the engine manufacturer's service procedure.
- Remove the water-pump cover and inspect the existing housing, plate, driveshaft keyway, and mating surfaces.
- Because the Mercury/Mariner configuration does not include a housing, replace or reuse the housing only after confirming that it is undamaged and compatible.
- Remove old gasket material and debris without damaging the sealing surfaces.
- Install the replacement service components in the correct orientation. Use an appropriate water-pump lubricant for impeller installation and do not use petroleum-based grease on the impeller.
- Reassemble the water-pump cover and lower unit, aligning the driveshaft, shift shaft, and water tube correctly.
- Tighten fasteners to the engine manufacturer's specified torque.
- Run the engine in water or with an appropriate flushing device and verify a steady tell-tale stream before normal operation.
Troubleshooting & FAQ
How do I confirm this kit fits my Mercury or Mariner engine?
Match all conditions, not just horsepower. The catalog lists 9.9 EFI models from serial number 1R00814 and 10, 15, and 20 EFI models from serial number 0R833820. Confirm the engine is a 4-stroke EFI model and compare the original water-pump reference number.
Does this Mercury/Mariner kit include the water-pump housing?
No. The company catalog identifies the Mercury/Mariner configuration as a water-pump service kit without housing. Inspect your existing housing and replace it separately if it is worn or damaged.
Can I use the same listing for a Nissan or Tohatsu outboard?
The company catalog separately lists MFS15E and MFS20E applications with reference numbers 3RS-87322-1 and 3RS-87322. Those records describe a housing-included service-kit configuration. Confirm the exact brand, model, stroke, and package configuration before ordering.
What are the signs of a failing water-pump impeller?
Common signs include a weak or intermittent tell-tale stream, overheating at idle or low speed, and a temperature warning. Stop operation and inspect the cooling system if overheating occurs.
What lubricant should be used during installation?
Use a suitable water-pump lubricant such as glycerin or a compatible silicone-based product as directed by the service procedure. Avoid petroleum-based grease on rubber impeller components.
Is this an OEM component?
This listing is for an aftermarket replacement service kit. The manufacturer reference numbers are provided for application and part comparison only.
Safety & Important Info
- Confirm the model, stroke, horsepower, serial range, and reference number before purchase.
- For the Mercury/Mariner configuration, the water-pump housing is not included.
- Do not operate an outboard with an uncertain or damaged cooling-system installation.
- Professional installation is recommended when removing the lower unit or servicing the cooling system.
About Sea Sierra
- Marine Parts Focus — We supply replacement components for routine outboard service and repair.
- Application-Based Listings — Fitment information is organized around engine model, stroke, horsepower, and serial conditions.
- Service Support — Compare your original part and package contents before installation to help ensure the correct configuration.
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