MerCruiser Exhaust Elbow Gasket 48042 | 27-48042

Exhaust Elbow Gasket — Part 48042

This is the genuine OEM gasket that seals the joint between the exhaust manifold, intermediate face plate, and exhaust elbow on selected older MerCruiser GM V8 exhaust systems. It is not a generic exhaust gasket — its specific location is the intermediate plate interface in TR and TRS-style closed-cooling exhaust assemblies. On some configurations, up to four gaskets are used per engine, one at each manifold-to-elbow joint.

Note: Similar MerCruiser engines may use gasket 997772 / 27-997772 instead. These are not automatically interchangeable — always confirm the correct part by your engine’s exhaust-system diagram, not displacement alone.

Part Number Reference

• Current OEM number: 48042 / 27-48042
• Related but different: 997772 / 27-997772 — used on other MCM/MIE configurations (search by part number to confirm which applies to your engine)

Compatible Applications

Fitment is exhaust-diagram specific. Confirm by engine serial number and the applicable exhaust manifold / elbow schematic.

• MCM 228 TR — GM V8 TR-style exhaust assembly
• MCM GM 350 V8 — Selected exhaust manifold configurations specifying 48042
• 280 TRS GM 350 V8 — Closed-cooling exhaust assemblies where diagram specifies 48042
• Additional older MerCruiser V8 applications — where the exhaust manifold diagram specifies 48042 at the elbow / intermediate plate joint

When This Part Needs Replacement

• The exhaust elbow is removed from the manifold for any reason
• Water or exhaust leakage is visible at the elbow-to-manifold joint
• The gasket is crushed, burned, torn, or hardened
• The intermediate face plate is being inspected or replaced
• The manifold or elbow itself is being replaced
• Corrosion is visible around the sealing surfaces

Exhaust elbow gaskets should not be reused once the joint has been separated.

Related Parts

• 74829 — Exhaust manifold-to-elbow face plate (search by part number)
• 60207 — Exhaust elbow-to-manifold plate on selected systems (search by part number)
• 73782 — Alternate elbow / manifold plate on selected TR applications (search by part number)
• 35048 — Exhaust elbow stud lockwasher (search by part number)
• 815504220 — Cooling hose clamp on applicable closed-cooling systems (search by part number)
• 997772 / 27-997772 — Alternate exhaust elbow gasket for other MCM/MIE configurations — confirm by diagram before substituting (search by part number)

Installation Notes

• Remove all old gasket material from the manifold and elbow sealing faces
• Inspect the intermediate plate for distortion or corrosion before reuse
• Check manifold and elbow sealing faces for pitting or corrosion
• Install new gaskets any time the joint is opened — never reuse the old gasket
• Follow the applicable MerCruiser tightening sequence and torque specification
• Inspect for water and exhaust leakage after reassembly

Parts Desk Insights

Most common customer issue: Ordering 997772 when the engine actually needs 48042 (or vice versa). Both are MerCruiser exhaust elbow gaskets for GM V8 engines, but they fit different exhaust-system configurations. If you pull the elbow and the gasket doesn’t match, you’ve got the wrong diagram. Always verify against the exhaust-manifold / elbow schematic for your specific engine serial number range.

Best use case: Essential for any exhaust manifold or elbow service on older MerCruiser TR and TRS V8 installations. If you’re replacing a manifold, elbow, or intermediate plate, order a full set of gaskets before starting the job — these should never be reused once disturbed.