Sierra Exhaust Manifold Riser 18-1907 | 3 in. / 76.2 mm Outlet
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Sierra Exhaust Manifold Riser 18-1907
- Part Number: 18-1907 (Sierra)
- Brand: Sierra
- Product Type: Exhaust Manifold Riser / Elbow
- Exhaust Outlet: 3 in. / 76.2 mm
- Application: Marine inboard and sterndrive center-riser exhaust systems
- UPC: 808282127411
Sierra 18-1907 is a cast marine exhaust manifold riser / elbow for selected center-riser exhaust manifold systems on inboard and sterndrive gasoline engines. It routes exhaust gases and engine cooling water from the exhaust manifold into the downstream marine exhaust hose. Sierra lists 18-1907 for direct use with manifolds 18-1997-1 and 18-1998-1. All Sierra exhaust risers are painted, packaged, and leak-tested before shipment.
Compatible Applications
Documented engine families and manifold systems:
- Ford 302 CID / 4.9L V8 — marine inboard applications
- Ford 351 CID / 5.8L V8 — marine inboard applications
- Selected GM-based marine engines (283, 305, 307, 327, 350 CID) when paired with compatible center-riser manifold configurations
- For use with Sierra exhaust manifold 18-1997-1 or 18-1998-1
Always confirm the existing exhaust manifold part number, riser part number, exhaust outlet diameter, and cooling-water gasket configuration before ordering. Exhaust riser fitment depends on the manifold and gasket arrangement, not engine displacement alone.
Compatible Gaskets & Mounting Hardware
- Open riser gasket — Sierra 18-2854
- Blocked riser gasket — Sierra 18-0476
- Open mounting kit — Sierra 18-4364
- Blocked mounting kit — Sierra 18-8535
The correct gasket type (open vs. blocked) depends on your engine’s cooling-system configuration. Confirm this before ordering gaskets or hardware.
Cross-Reference Part Numbers
- Sierra: 18-1907
- Supplier/Internal Reference: 47-1907
- Barr: 20-0102
- Indmar: 53-2009
- Indmar: 53-2018
When to Replace the Riser
- Internal cooling-water passages are restricted by corrosion or scale
- Rust scaling is visible inside the exhaust passage
- Cooling water leaks externally at the riser or manifold joint
- Water intrusion is found near the manifold/riser gasket surface
- The casting is cracked or the outlet neck has deteriorated
- Exhaust-system overheating has occurred
Note: Marine exhaust risers operate in a continuous mix of heat, exhaust gas, and cooling water. Internal deterioration often progresses well before significant exterior damage becomes visible. Inspect the internal passages any time the riser is removed.
Installation Notes
- Inspect the manifold sealing surface thoroughly and remove all old gasket material
- Determine whether your application requires an open or blocked riser gasket before ordering hardware
- Inspect the manifold internally for corrosion before fitting the new riser
- Replace corroded mounting fasteners rather than reusing them
- Torque all fasteners to the engine or manifold manufacturer’s specification
- Inspect the 3 in. / 76.2 mm exhaust hose, bellows, and clamps during the same service
- Check for exhaust and cooling-water leaks at startup before returning to service
Parts Desk Insights
Best use case: Sierra 18-1907 is the right riser for any boat running Sierra exhaust manifolds 18-1997-1 or 18-1998-1, or engines cross-referencing Barr 20-0102 or Indmar 53-2009 / 53-2018. The 3 in. / 76.2 mm outlet and center-riser design make it a direct-fit replacement for scheduled exhaust system service — particularly on Ford 302 and 351 V8 marine applications and compatible GM-block installations using the same manifold family.
Common issue: The most frequent ordering mistake is selecting a riser by engine displacement without confirming the manifold part number and cooling-passage gasket type. Open and blocked cooling configurations use different gaskets that are not interchangeable — ordering the wrong gasket alongside an otherwise correct riser is a common service call. Always identify the manifold number and gasket configuration before completing the order. Internal riser corrosion is also frequently missed during visual inspection; always probe the internal passages before deciding whether a riser or a full manifold-and-riser replacement is needed.
Shop all exhaust components in our Exhaust Systems collection or browse Engine Parts & Maintenance for related components.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
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