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Outboard Maintenance Kit – Fits Mercury/Mariner 4-6 HP 4-Stroke (Replaces 8M0120836, 3GR-87500-0)
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Outboard Maintenance Kit – Fits Mercury/Mariner 4-6 HP 4-Stroke (Replaces 8M0120836, 3GR-87500-0)
This comprehensive maintenance kit is designed for Mercury and Mariner 4HP, 5HP, and 6HP 4-Stroke outboard motors. It provides all the necessary components for your routine 300-hour service interval.
This kit is a direct replacement for Mercury/Mariner part numbers 8M0120836 and 3GR-87500-0.
- Includes engine-specific replacement components for a complete service.
- Designed for gasoline-fueled 4-stroke engines.
- Contains all parts needed for the recommended 300-hour service interval.
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand | Part Number |
|---|---|
| Mercury/Mariner | 8M0120836 |
| Mercury/Mariner | 3GR-87500-0 |
Compatible Engine Models
Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.
| Brand | Model | Rated HP | Stroke | OEM Part No. | Notes |
|---|---|---|---|---|---|
| Mercury/Mariner | 4HP | 4 | 4-Stroke | 8M0120836 | Serial numbers 0R411838 and above |
| Mercury/Mariner | 5HP | 5 | 4-Stroke | 8M0120836 | Serial numbers 0R411838 and above |
| Mercury/Mariner | 6HP | 6 | 4-Stroke | 8M0120836 | Serial numbers 0R411838 and above |
Technical Specifications
| Specification | Value |
|---|---|
| Product Type | Outboard Maintenance Service Kit |
| Installation | Engine-specific replacement components |
| Fuel Type | Gasoline |
| Housing Material | Multiple materials (Neoprene impeller) |
| Weight | 0.045 kg (0.1 lb) |
| Other Technical Attributes | 300-Hour service interval maintenance kit |
Package Contents
- 1 x Water Pump Impeller (47-16154-3)
- 1 x Cotter Pin (8150264)
- 1 x Pin Key (28-16155)
- 1 x Thermostat (804540)
- 1 x Thermostat Gasket (27-8M0214960)
- 1 x O-Ring (25-16131)
- 1 x Oil Seal (16130/26-16130)
- 1 x Fuel Filter (35-8M0157133)
- 1 x Gaskets (8035161)
- 2 x Drain Gasket (27-95220)
Installation Guide
- Ensure the engine is off and the battery is disconnected for safety.
- Access the lower unit to service the water pump; remove the old impeller, seals, and key.
- Install the new water pump impeller (47-16154-3) and related seals.
- Locate and replace the thermostat (804540) and its gasket.
- Find the existing fuel filter and replace it with the new fuel filter (35-8M0157133).
- Replace the oil drain screw gaskets during your oil change.
- Reassemble all components securely.
- Reconnect the battery and start the engine to check for proper function and leaks.
Troubleshooting & FAQ
Q: How do I confirm this fits my engine?
A: This kit is specifically for Mercury/Mariner 4HP, 5HP, and 6HP 4-stroke outboard motors with serial numbers 0R411838 and above. Please verify your engine model and serial number before ordering.
Q: How often should I perform this service?
A: This is a 300-hour service kit, intended for routine maintenance as recommended by the manufacturer to maintain engine performance and reliability.
Q: What are the signs I need to replace these parts?
A: Common indicators include engine overheating (impeller failure), poor fuel delivery or stalling (clogged fuel filter), or inconsistent engine temperature (faulty thermostat). Regular service prevents these issues.
Q: OEM vs. Aftermarket?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.
Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.
Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.
Important Notes
- Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
- This product is an aftermarket replacement part and is not an OEM component.
- Professional installation is recommended to ensure safety and optimal performance.
Why Choose JLM MARINE?
- Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
- Fast Global Shipping: Free delivery worldwide in 5–15 days.
- Direct from Manufacturer: Competitive pricing without compromising quality.
We can ship to virtually any address in the world with free shipping available for most regions.
For our typical US and Canadian customers , our shipping timeframes are as follows:
- Amazon FBA: orders will be delivered within 1-5 business days after placing the order (during certain special periods such as major promotions, Christmas, etc., the delivery time of Amazon FBA may be affected).
- US warehouse shipment: orders will be delivered within 5 days after placing the order.
- China warehouse shipment: orders will be delivered about 12 days after placing the order.
When you place an order, we will estimate shipping and delivery dates for you based on the availability of your items and the shipping options you choose. Depending on the shipping provider you choose, shipping date estimates may appear on the shipping quotes page.
Please also note that the shipping rates for many items we sell are weight-based. The weight of any such item can be found on its detail page. To reflect the policies of the shipping companies we use, all weights will be rounded up to the next full pound.
Founded in 2002, JLM Marine has established itself as a dedicated manufacturer of high-quality marine parts, based in China. Our commitment to excellence in manufacturing has earned us the trust of top marine brands globally.
As a direct supplier, we bypass intermediaries, which allows us to offer competitive prices without compromising on quality. This approach not only supports cost-efficiency but also ensures that our customers receive the best value directly from the source.
We are excited to expand our reach through retail channels, bringing our expertise and commitment to quality directly to boat owners and enthusiasts worldwide.
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