Holley Carburetor Base Gasket – Fits Mercury/Mercruiser 215/225/255 Ford V8 (Replaces 27-65577)

$4.86

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Product Details

This Holley Carburetor Base Gasket creates a secure seal between the carburetor and intake manifold. It is designed specifically for Mercury/Mercruiser sterndrive and inboard models equipped with Ford 302 V8 (215/225 HP) and Ford 351 V8 (255 HP) engines manufactured between 1970 and 1974.

This part is a direct replacement for Mercury/Mercruiser 27-65577, Sierra 18-0357, and Quicksilver 65577.

Installs directly between the carburetor and intake manifold.
Engineered for use with gasoline fuel systems.
Sold in a convenient pack of two gaskets.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Brand	Part Number
Mercury/Mercruiser	27-65577
Quicksilver	65577
Sierra	18-0357

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For Mercruiser applications, it is critical to verify your engine's model, year, and serial number range to ensure correct fitment.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Mercruiser	215 MCM/MIE (Ford)	215	4-Stroke	1970–1972	27-65577	Serial Range: 2781153-3385720, Original Carb #1356-4066, MFG Model #C9FF9510E H4/4160
Mercruiser	225 MCM/MIE (Ford)	225	4-Stroke	1973–1974	27-65577	Serial Range: 3385721-4166999, Original Carb #1356-5155, MFG Model #D2JL9510C H4/4160
Mercruiser	225-S (Ford)	225	4-Stroke	1973–1974	27-65577	Serial Range: 3385721-4166999
Mercruiser	255 MCM/MIE (Ford)	255	4-Stroke	1973–1974	27-65577	Serial Range: 3258728-4175499, Original Carb #1356-5169, MFG Model #D2JL9510E H4/4160

Technical Specs

Product Type: Carburetor Base Gasket
Material: Composite
Installation: Direct mount between carburetor and intake manifold
Fuel Type: Gasoline
Dimensions: 10.88" H x 8.0" W x 1.13" L
Sold As: Pack of 2

What’s in the Box

2 x Carburetor Base Gasket (replaces 27-65577)

Installation Notes

Disconnect the boat's battery and relieve any pressure in the fuel system for safety.
Carefully note and disconnect all fuel lines, throttle linkages, and vacuum hoses attached to the carburetor.
Unbolt and remove the carburetor from the intake manifold.
Remove the old base gasket. Thoroughly clean both the carburetor base and the intake manifold mating surfaces to ensure a clean, flat surface.
Position the new gasket onto the intake manifold, aligning it with the mounting studs or bolt holes.
Carefully place the carburetor onto the new gasket.
Tighten the carburetor mounting nuts or bolts in a progressive, crisscross pattern to the manufacturer's recommended torque specification.
Reconnect all fuel lines, linkages, and hoses.
Reconnect the battery, start the engine, and carefully inspect for any fuel or vacuum leaks around the gasket.

Troubleshooting & FAQ

How do I know if this gasket fits my engine?

Compare your engine details against the Engine & Model Compatibility table. It is crucial to match the brand, model, horsepower, year, and especially the serial number range to confirm correct fitment for your Mercruiser engine.

What are signs of a failing carburetor base gasket?

Common symptoms of a bad gasket include a vacuum leak (which can cause a hissing sound, rough or high idle, and stalling), poor engine performance, and decreased fuel economy. A visual inspection might show cracks or degradation of the old gasket material.

Does this gasket require sealant during installation?

This composite gasket is designed to be installed dry. Applying sealant can sometimes interfere with a proper seal. Always follow the procedures in your engine's official service manual, but typically, no additional sealant is needed.

How often should this gasket be replaced?

The carburetor base gasket should be replaced every time the carburetor is removed from the intake manifold for service or cleaning. It is a wear item that degrades over time from heat and fuel exposure.

Why is this sold as a pack of two?

This part is sold in a pack of two for user convenience. This is helpful for professional technicians servicing multiple engines or to have a spare on hand for future maintenance. You will only need one gasket per carburetor installation.

Is this an OEM part?

This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.

What are the shipping speed and cost?

We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

What is the warranty and return policy?

Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.

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

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