27-99777-2 Open Exhaust Elbow Gasket for MerCruiser 120 140 2.5L 3.0L
27-99777-2 Open Exhaust Elbow Gasket for MerCruiser 120 140 2.5L 3.0L is backordered and will ship as soon as it is back in stock.
Care information
Care information
Display general product information or specific product information using metafields.
Delivery and Shipping
Delivery and Shipping
Add some general information about your delivery and shipping policies.
27-99777-2 Open Exhaust Elbow Gasket for MerCruiser 120 140 2.5L 3.0L
27-99777-2 Open Exhaust Elbow Gasket for MerCruiser 120 140 2.5L 3.0L is backordered and will ship as soon as it is back in stock.
SERDAMARINE / MARINE EXHAUST PARTS
Rear-Riser Open Exhaust Manifold-to-Elbow Gasket
This rear-riser open gasket services the exhaust manifold-to-elbow or adaptor joint on applicable MerCruiser 4-cylinder, 6-cylinder, and V8 engines, including 120, 140, 2.5L, 3.0L, and 3.0LX series applications. It corresponds to primary OEM reference 27-99777-2 and is distinct from the closed-cooling gasket configuration referenced as MerCruiser 27-92720 / GLM 32630.
Engine Applications
Engine model alone is not sufficient to distinguish between open and closed-cooling gasket versions; match your engine model, production year, and existing rear-riser open-gasket configuration at the exhaust manifold-to-elbow or adaptor joint before ordering.
- MerCruiser 4-Cyl. & 6-Cyl. (except 120hp) — Years: 1968–1982. Joint location: Exhaust manifold to elbow or adaptor. Configuration: Rear-riser open gasket. Fits when specified
- MerCruiser All V8 — Years: 1978–1982. Joint location: Exhaust manifold to elbow or adaptor. Configuration: Rear-riser open gasket. Fits when specified
- MerCruiser Model 140 — Engine configuration: Inline 4, GM 181 CID, 4-Cyl. Years: 1968–1982. Joint location: Exhaust manifold to elbow or adaptor. Configuration: Rear-riser open gasket. Fits when specified
- MerCruiser Model 120 / 140 — Engine configuration: Inline 4, 153 / 181 CID, 4-Cyl. Years: 1982–1995. Joint location: Exhaust manifold to elbow or adaptor. Configuration: Rear-riser open gasket. Fits when specified
- MerCruiser 2.5L — Years: 1983–1994. Joint location: Exhaust manifold to elbow or adaptor. Configuration: Rear-riser open gasket. Fits when specified
- MerCruiser 3.0L — Years: 1983–1994. Joint location: Exhaust manifold to elbow or adaptor. Configuration: Rear-riser open gasket. Fits when specified
- MerCruiser Model 3.0LX / 3.0L — Engine configuration: Inline 4, GM 181 CID, 4-Cyl. Years: 1990 & up. Joint location: Exhaust manifold to elbow or adaptor. Configuration: Rear-riser open gasket. Fits when specified
Not Suitable For
- MerCruiser 120hp (1968–1982) — Excluded from the 1968–1982 4/6-Cyl. application range. Not suitable
- Closed-Cooling Gasket Applications (MerCruiser 27-92720 / GLM 32630) — This listing is the open rear-riser gasket version, not the closed-cooling gasket configuration. Not suitable
Reference Numbers
The numbers below are provided for part identification and cross-reference only; they do not alone guarantee interchangeability across different gasket configurations or indicate manufacturer identity.
| MerCruiser Stern / Out Drive Reference | 27-99777-2, 27-997772, 27-99777Q02, 99777Q02, 997771, 99777B2, 27-997771, 27-99777B2, 27-52076, 52076 |
|---|---|
| Mercury Mariner Reference | 27-99777 |
| OMC Reference | 0508615 |
| Aftermarket Reference (GLM) | GLM31520, 31520 |
| Aftermarket Reference (Sierra) | 18-2833, 18-2833-9 |
| Aftermarket Reference (RECMAR) | REC27-99777Q02 |
| Different Configuration (Not This Part) | MerCruiser 27-92720, GLM 32630 (Closed-cooling gasket version) |
Supplied Parts
- Rear-riser open exhaust manifold-to-elbow gasket
Service & Installation Notes
General service guidance only. Use the service manual for your exact engine and exhaust configuration.
- Ensure the engine is shut off, completely cool, and secured against accidental starting before servicing any exhaust joint.
- Support the exhaust elbow or adaptor during disassembly to prevent strain on connected exhaust hoses or mounting hardware.
- Clean the mating surfaces on both the exhaust manifold and the elbow or adaptor thoroughly, taking care not to gouge or damage the sealing faces.
- Compare the port openings of the new rear-riser open gasket directly against the joint passages to verify that it matches the required open-gasket configuration; never substitute an open gasket where a closed-cooling gasket is specified.
- Reassemble the joint and tighten fasteners according to the sequence and specifications in your engine service manual, then inspect the joint during initial operation and stop the engine immediately if any exhaust or water leak is detected.
The Serdamarine Approach
Exhaust parts need a configuration match. Serdamarine focuses on marine exhaust manifolds and their related service parts. Application details, connection requirements and public reference numbers are presented together to support part selection.
Questions Before Replacement
How do I distinguish this gasket from the closed-cooling version?
This part is the rear-riser open gasket for the exhaust manifold-to-elbow or adaptor joint, identified by references such as MerCruiser 27-99777-2, 27-99777Q02, and GLM 31520. The closed-cooling alternative uses a different design and is referenced under MerCruiser 27-92720 or GLM 32630.
Does this gasket fit all MerCruiser 120hp inline 4-cylinder engines?
No. For 1968–1982 4-cylinder and 6-cylinder applications, the 120hp model is specifically excluded. However, it is listed for Model 120 / 140 inline 4-cylinder (153 / 181 CID) engines from 1982–1995 when equipped with the rear-riser open-gasket configuration.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
Product features
Use this section to highlight specific product features to your customers.
Product comparison grid
Add content here to explain a bit about the range of products on offer and which ones may be most suitable for your customers.
