Water Pump Cover Gasket – Fits Yanmar 2GM, 3GM Series Marine Engines (Replaces 104211-42090)
Water Pump Cover Gasket – Fits Yanmar 2GM, 3GM Series Marine Engines (Replaces 104211-42090) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Water Pump Cover Gasket – Fits Yanmar 2GM, 3GM Series Marine Engine...
Product Details
This Sea Water Pump Cover Plate Gasket provides a reliable seal for the raw water pump on a wide range of Yanmar marine diesel engines. It is designed for the 1GM, 2GM, and 3GM series, including popular models like the 2GM20 and 3GM30, ensuring a precise fit and restoring pump efficiency.
This part is a direct replacement for Yanmar OEM part number 104211-42090.
- Designed for marine diesel environments.
- Installs with 6 bolts on a 48mm PCD.
- Engineered for a precise seal to prevent leaks.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yanmar | 104211-42090 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This gasket is compatible with a wide array of Yanmar diesel engines, from the YSE series to the modern JH and YM series. Please verify your specific model for a guaranteed fit.
| Brand | Model | OEM Part No. | Notes |
|---|---|---|---|
| Yanmar | 1GM | 104211-42090 | |
| Yanmar | 1GM10 | 104211-42090 | |
| Yanmar | 2GM | 104211-42090 | |
| Yanmar | 2GM20, 2GM20VE, 2GM20B, 2GM20C | 104211-42090 | |
| Yanmar | 2GM20-YEU | 104211-42090 | |
| Yanmar | 2GM20F, 2GM20F-YEU | 104211-42090 | |
| Yanmar | 2GMF | 104211-42090 | |
| Yanmar | 2GML, 2GMYE-EC | 104211-42090 | |
| Yanmar | 2GMZ | 104211-42090 | |
| Yanmar | 2QM | 104211-42090 | |
| Yanmar | 2QM15 | 104211-42090 | |
| Yanmar | 2QM20 | 104211-42090 | |
| Yanmar | 2YM15 | 104211-42090 | |
| Yanmar | 3GM | 104211-42090 | |
| Yanmar | 3GM30, 3GM30VE, 3GM30B, 3GM30C | 104211-42090 | |
| Yanmar | 3GM30-YEU, 3GM30F-YEU | 104211-42090 | |
| Yanmar | 3GMD | 104211-42090 | |
| Yanmar | 3GMF | 104211-42090 | |
| Yanmar | 3GMLE | 104211-42090 | |
| Yanmar | 3HM, 3HM35, 3HM35F, 3HMF | 104211-42090 | |
| Yanmar | 3JH2, 3JH2-TE, 3JH2BE, 3JH2TBE | 104211-42090 | |
| Yanmar | 3JH3, 3JH3E | 104211-42090 | |
| Yanmar | 3JH4E, 3JH5E | 104211-42090 | |
| Yanmar | 3QM, 3QM30, 3QM30F | 104211-42090 | |
| Yanmar | 3YM20, 3YM30 | 104211-42090 | |
| Yanmar | SB8, SB12 | 104211-42090 | |
| Yanmar | SVE8, SVE12 | 104211-42090 | |
| Yanmar | YSB8, YSB12 | 104211-42090 | |
| Yanmar | YSE8, YSE12 | 104211-42090 | |
| Yanmar | YSM8, YSM12 | 104211-42090 |
Technical Specs
- Product Type
- Sea Water Pump Cover Plate Gasket
- Installation
- 6 bolt holes on 48mm PCD
- Fuel Type
- Marine Diesel
- Connection
- Bolted
- Housing Material
- Gasket Material
- Product Dimensions
- 6.0 in L x 6.0 in W x 0.1 in H
- Warranty
- 6 months
What’s in the Box
- 1 x Sea Water Pump Cover Plate Gasket (Replaces 104211-42090)
Installation Notes
- Disconnect the vessel's battery and close the engine's raw water intake seacock.
- Place a suitable container below the pump to catch any residual coolant or water.
- Carefully loosen and remove the six bolts securing the water pump cover.
- Remove the old cover and gasket. You may need a putty knife to gently pry them off if stuck.
- Thoroughly clean both the pump housing and cover mating surfaces. Ensure they are free of old gasket material, corrosion, and debris.
- Position the new gasket onto the pump housing, aligning the bolt holes.
- Place the cover over the gasket and thread the bolts in by hand.
- Tighten the bolts in a star pattern to ensure even pressure. Do not overtighten.
- Open the seacock and reconnect the battery.
- Start the engine and carefully inspect the pump cover for any signs of leaks.
Troubleshooting & FAQ
How do I confirm this gasket fits my specific Yanmar engine?
Your primary reference should be the part number. If your existing gasket or service manual specifies part number 104211-42090, this part is a direct cross-reference. You can also check the extensive list of compatible engine models on this page.
What are the signs of a failing water pump gasket?
Common signs include visible water drips or salt-crystal buildup around the pump cover seam, unexplained loss of coolant, and engine overheating alarms caused by reduced water flow.
How often should this sea water pump gasket be replaced?
It is best practice to replace the gasket every time you service the sea water pump impeller, which is typically recommended annually or every 200-300 engine hours, depending on use and water conditions.
Do I need to apply a sealant to this gasket during installation?
Generally, new gaskets of this type are designed to be installed dry. Applying sealant can sometimes interfere with a proper seal. However, if the pump housing surfaces are slightly pitted or scored, a very thin layer of a non-hardening, marine-grade sealant may be used. Always consult your engine's service manual.
What is the difference between an OEM and an aftermarket part?
This listing is for an aftermarket replacement, not an OEM Yanmar part. It is engineered to meet or exceed original equipment specifications for fit, form, and function, using comparable materials. Our parts are manufactured in an ISO 9002 certified facility and are batch-inspected to ensure quality and consistency.
How fast is shipping?
We ship worldwide, with most orders arriving in 5–15 days via standard shipping. Expedited shipping options are available at checkout for most regions. Standard shipping is free.
What is the warranty and return policy?
This part is covered by a 6-month warranty against any manufacturing defects under normal operating conditions. If you encounter an issue, please contact our support team with your order number. We accept returns for unused items in their original packaging within our standard return window.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
Payment & Security
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