# 2774830 Mercury MerCruiser Gasket | Genuine Quicksilver OEM Part

🔧 Product Description

  

Genuine Quicksilver Thermostat Housing to Reservoir Gasket - Part Number: 27-74830

  

A genuine Quicksilver thermostat housing to reservoir gasket for MerCruiser 470 3.7L / 224 CID inline 4-cylinder engines. This gasket seals the thermostat housing to reservoir interface on the MerCruiser 470 cooling system and is used on 1976-1982 470 MCM / MIE applications where specified.

  

⚙️ Key Features

  

• Genuine Quicksilver OEM gasket

• Correct Mercury part number 27-74830

• Thermostat housing to reservoir gasket

• Fits MerCruiser 470 MCM / MIE 224 CID inline 4-cylinder applications where specified

• Cross-references with Sierra, GLM and Barr Marine gasket references

  

🔄 Supersession & Cross Reference

  

OEM Supersession Chain:

  

• 27-74830 current OEM service reference

  

OEM / Related Numbers:

  

• 27-74830

• 74830

• 2774830

• 76270T related thermostat reference for early 470 / 485 cooling system

• 991551 related thermostat reference for later 470 cooling system applications

  

Aftermarket / Verified Equivalents:

  

• Sierra: 18-2843

• GLM: 31840

• Barr Marine: MC47-27-74830

  

🚤 Compatibility

  

Commonly used on:

  

• MerCruiser 470 thermostat housing to reservoir gasket applications

• MerCruiser 224 CID inline 4-cylinder cooling systems

  

Typically suits:

  

• Engine models:

• MerCruiser 470 MCM / MIE 224 CID I/L4 - 1976-1982, serial 4208730 to 6218036

• MerCruiser 470 2BBL Mercury 224 I/L4 - 1976-1979, serial 4208730 to 5520114

• MerCruiser 470 2BBL Mercury 224 I/L4 - 1980-1982, serial 5520115 to 6218036

• MerCruiser 470 inboard exhaust manifold and elbow applications where 27-74830 is specified

• MerCruiser 470 MCM exhaust manifold and elbow applications where 27-74830 is specified

• MerCruiser 470 / 485 cooling system applications with thermostat housing to reservoir gasket 27-74830 and serial 6218036 and below

  

• Engine Type: MerCruiser 470 / 224 CID inline 4-cylinder petrol engine

• Year Range: 1976-1982 where specified

• System Type: Thermostat housing to reservoir gasket / cooling system gasket

  

🔌 Function

  

The gasket seals the thermostat housing to reservoir joint, helping prevent cooling-water leakage and maintaining correct flow through the thermostat housing and reservoir assembly.

  

Common signs of failure:

  

• Water leak at thermostat housing / reservoir joint

• Rust staining or corrosion around housing joint

• Cooling-system seepage after thermostat service

• Gasket torn during housing removal

• Replacement required during thermostat housing or exhaust manifold service

  

📦 Condition

  

• Genuine Quicksilver part

• Brand new

• Supplied in original or equivalent packaging

## Details

- **Price:** 11.5 AUD
- **Vendor:** Quicksilver
- **Tags:** Quicksilver Marine Parts | Oils Service Kits & Engine Components

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 11.50 AUD | In stock |

## Images

- 2774830 Mercury MerCruiser Gasket | Genuine Quicksilver OEM Part

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> Source: [Sawley's Auto and Marine](www.sawleysautoandmarine.com.au/products/2774830-mercury-mercruiser-gasket-genuine-quicksilver-oem-part)
> Updated: 2026-05-17