Exhaust Elbow Gasket Set 27-8637251 18-1970-2 for MerCruiser 4.3 5.0 5.7 6.2L 2 Pack
Exhaust Elbow Gasket Set 27-8637251 18-1970-2 for MerCruiser 4.3 5.0 5.7 6.2L 2 Pack
Product Overview
Exhaust elbow gasket set for MerCruiser V6 and V8 stern drive engines, the two high temperature composite gaskets that seal the joint between the exhaust manifold and the centre riser elbow on fresh water cooled motors. They replace 27-8637251, 27-860231 and 27-41811, cross to Sierra 18-1970-2 and 18-1976-2, and they ship as a pack of 2 in an 18 x 15 x 3 cm bag.
They fit 4.3L, 5.0L, 5.7L and 6.2L motors plus the 454 MAG and 502 MAG big blocks, on centre riser manifolds with a 3 in or 4 in riser, built from the early 1980s to 2002. They are not for dry joint exhaust, which uses a different sealing system and will not take these gaskets.
A weeping riser gasket shows up as a rust stain down the side of the manifold or a drop of water under the elbow after a run, and it is easy to ignore until it becomes a hydraulic lock in a cylinder. Water does not need to pour to write off a motor; a slow drip into an open exhaust valve over a winter is enough.
Specifications
| Specification | Detail |
|---|---|
| Condition | New / New with tags |
| Type | Exhaust elbow gasket set, manifold to riser |
| Material | High temperature composite |
| Fits | MerCruiser 4.3L, 5.0L, 5.7L, 6.2L, 454 MAG, 502 MAG |
| Riser Size | 3 in (76 mm) or 4 in (102 mm) centre riser |
| Years | Early 1980s to 2002 |
| Contents | 2 exhaust elbow gaskets |
| Net Weight | 33 g including packaging |
| Pack Size | 180 mm x 150 mm x 30 mm |
| Warranty | 3 year |
OEM Cross Reference
| Component | OEM Part Numbers |
|---|---|
| Exhaust elbow gasket | 27-8637251 |
| Exhaust elbow gasket, alternate | 27-860231, 27-41811, 27-863725 |
| Sierra cross reference | 18-1970-2, 18-1976-2 |
| Barr manifold cross reference | MC-20-44354, MC-20-98504 |
| Manifold cross reference | 44354A3, 44354A9, 44354A10, 44354A13 |
| Manifold cross reference, continued | 807914A1, 807988A2, 807988A03, 95755A2, 98503A2, 98504A3 |
Compatible Engines
| Engine | Displacement | Typical Power | Years |
|---|---|---|---|
| MerCruiser 4.3L V6 | 262 CID | 190 to 220 HP | 1980s to 2002 |
| MerCruiser 5.0L V8 | 305 CID | 220 to 260 HP | 1980s to 2002 |
| MerCruiser 5.7L V8 | 350 CID | 250 to 300 HP | 1980s to 2002 |
| MerCruiser 6.2L V8 | 377 CID | 320 HP | 1980s to 2002 |
| MerCruiser 454 MAG | 454 CID | 330 to 385 HP | 1980s to 2002 |
| MerCruiser 502 MAG | 502 CID | 415 to 425 HP | 1980s to 2002 |
What's Included
| Component | Detail | Qty |
|---|---|---|
| Exhaust elbow gasket | 27-8637251 pattern, composite | 2 |
| Riser bolts | Not included, reuse sound originals | 0 |
| Manifold gasket | Not included | 0 |
| Sealant | Not required, fit these gaskets dry | 0 |
Leak Signs At The Riser
| What You See | What It Means | What To Do |
|---|---|---|
| Rust stain down the manifold | Gasket weeping water | New gasket set before storage |
| Water drip under the elbow | Joint faces not sealing | New gaskets, clean both faces |
| White crust at the joint | Salt water drying at the leak | New gaskets, check the faces for pitting |
| Riser bolts rusted solid | Old gasket joint left too long | Soak the bolts, expect to replace them |
| Exhaust note got louder | Blown gasket at the elbow | New gasket set, check for warping |
| Milky oil or a locked motor | Water into a cylinder | Stop running it, strip and inspect |
Fitting Notes
| Step | Action |
|---|---|
| 1 | Confirm the motor is fresh water cooled with a centre riser manifold |
| 2 | Drain the coolant and the exhaust water before anything is undone |
| 3 | Undo the riser bolts and tap the riser lightly to break the old seal |
| 4 | Clean both faces back to bare metal, no old gasket material left |
| 5 | Check both faces with a straight edge for warping or pitting |
| 6 | Fit the new gaskets dry, no sealant, lined up on the bolt holes |
| 7 | Torque the riser bolts in a criss cross pattern to the factory figure |
| 8 | Refill, run to temperature and check the joint for leaks before launch |
Condition & Warranty
| Item | Detail |
|---|---|
| Condition | New / New with tags |
| Warranty | 3 year |
| Packaging | Sealed retail packaging |
Before You Buy
- Two gaskets per pack, one pack does one elbow joint
- Fits MerCruiser 4.3L, 5.0L, 5.7L, 6.2L, 454 MAG and 502 MAG
- Replaces 27-8637251, 27-860231, 27-41811 and 27-863725
- Crosses to Sierra 18-1970-2 and 18-1976-2
- For centre riser manifolds with a 3 in or 4 in riser, early 1980s to 2002
- Not for dry joint exhaust systems
- 30-Day Easy Returns
- Ships from our warehouse with tracking
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Before You Buy
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