27887978 Mercury MerCruiser Gasket | Genuine Quicksilver OEM Part
27887978 Mercury MerCruiser Gasket | Genuine Quicksilver OEM Part
Couldn't load pickup availability
✓ Authorised Volvo Penta Dealer · Marine & auto specialists · Ships Australia-wide
🔧 Product Description
Genuine Quicksilver Thermostat Gasket / Seal - Part Number: 27-887978
Genuine Quicksilver thermostat gasket / seal used on Mercury and Mariner outboard thermostat assemblies. This gasket is part of the 27-62386 / 27-62386001 / 27-887978 family and is used across a wide range of Mercury / Mariner outboards where the thermostat housing diagram specifies this rubber thermostat seal.
⚙️ Key Features
- Genuine Quicksilver OEM thermostat gasket
- Correct Mercury part number 27-887978
- Listing reference: 27887978
- Rubber thermostat seal / gasket
- Supersedes earlier 27-62386 / 27-62386001 family references where specified
- Used on Mercury / Mariner outboards across broad HP ranges
🚤 Compatibility
Commonly used on
- Mercury / Mariner outboard thermostat assemblies
- Thermostat housing reseal service
- Outboard cooling-system maintenance where rubber thermostat seal 27-887978 is specified
Typically suits
- Engine models:
- Mercury / Mariner 8HP through 400HP outboard thermostat seal applications where 27-887978 is specified
- Mercury 10HP to 300HP outboards using the 27-62386 / 27-887978 thermostat seal family
- Mercury 75HP, 90HP, 115HP and 125HP outboard thermostat assemblies where specified
- Mercury V6 135HP, 150HP, 175HP, 200HP, 225HP and 250HP thermostat housings where specified
- Mercury OptiMax / DFI thermostat applications using seal 27-887978
- Mercury Verado and FourStroke thermostat service applications where 27-887978 is listed
- Mariner matching outboard thermostat assemblies using the same seal family
- HP Range: commonly 8HP - 400HP where specified
- Engine Type: Mercury / Mariner outboard cooling systems
- System Type: Thermostat gasket / rubber thermostat seal
🔌 Function
The gasket seals the thermostat in the housing so cooling water flows through the intended passages and does not leak around the thermostat cover.
⚠️ Common Signs of Failure
- Cooling water leak at thermostat cover
- Thermostat removed and seal disturbed
- Rubber seal brittle, flattened or swollen
- Salt or corrosion around thermostat housing
- Overheating after poor thermostat seal
- Scheduled thermostat service due
🔄 Supersession & Cross Reference
OEM Supersession Chain
- 27-887978 current OEM thermostat gasket reference
- 27-62386001 earlier OEM thermostat seal reference
- 27-62386 earlier OEM thermostat seal reference
- 62386B related earlier thermostat seal reference
OEM / Related Numbers
- 27-887978
- 887978
- 27887978
- 27-62386001
- 62386001
- 27-62386
- 62386
- 62386B
- Thermostat gasket
- Thermostat seal
- Rubber thermostat gasket
Aftermarket / Verified Equivalents
- Sierra: 18-0182
- Mallory: 9-60002
- GLM / aftermarket reference: 30610
- Aftermarket reference: 424
- Aftermarket reference: 540-32
- Recmar: REC27-62386001
- Aftermarket thermostat seal equivalents for 27-887978 / 27-62386 applications
📦 Condition
- Genuine Quicksilver part
- Brand new
- Supplied in original or equivalent packaging
Shipping & Delivery
Shipping & Delivery
Flat-rate shipping Australia-wide — $14.99 per order, no matter how many parts you add. Orders dispatch from our Kadina, South Australia store. Need it urgently or want to collect in person? Call us on 0412 532 984 before ordering.
Returns & Warranty
Returns & Warranty
14-day change-of-mind returns — if it's not right or you ordered the wrong part, send it back within 14 days in new, unused condition for a refund or exchange. Manufacturer warranties apply to new parts. Full details in our Refunds & Returns policy.
Not sure this fits?
Not sure this fits?
Ask us before you buy — we check part numbers and fitment every day. Call 0412 532 984 (Mon–Fri 8.30am–4.30pm) or message us through the contact page with your engine or vehicle details.
Share
