Mercury MerCruiser OEM 45° Exhaust Elbow Hose Fitting 865159 | Replaces 92499

Mercury / MerCruiser OEM 45° Exhaust Elbow Hose Fitting — Part No. 865159 / 22-865159

About This Part

The 865159 / 22-865159 is a genuine Mercury Marine / MerCruiser OEM 45-degree exhaust elbow hose fitting used on selected MerCruiser exhaust assemblies. It installs in the exhaust elbow to provide the angled cooling-hose connection required by the factory exhaust-cooling routing. 865159 is the current Mercury replacement for the earlier 92499 / 22-92499 — the current part may differ slightly in appearance from the superseded number while remaining the functional replacement.

Important: Mercury uses both 45-degree and straight fittings on otherwise similar exhaust elbows. The fitting angle is set by the factory cooling-hose routing — confirm your original fitting angle from the diagram before ordering. The straight-outlet equivalent is 866725.

Compatible Applications

Confirm the engine model, serial number, and exhaust-system diagram before ordering. Documented applications include selected MerCruiser engines:

• 4.3L / 262 CID V6
• 5.0L / 305 CID V8
• 5.7L / 350 CID V8 (including 350 MAG and 350 MAG Alpha)
• 7.4L / 454 CID V8 (including 454 MAG Bravo)
• 502 MAG / 502 CID V8
• 7.3L Navistar diesel
• Selected MIE inboard configurations

Applications span multiple serial ranges from the 1980s through later service configurations. Use the specific exhaust-system diagram for your engine serial number for final fitment confirmation.

Fitment Notice

Do not substitute the straight 866725 fitting where your original exhaust assembly specifies the 45-degree 865159, or vice versa. The outlet angle determines how the cooling hose routes away from the elbow — using the wrong fitting can result in hose kinking, poor routing, or interference with adjacent components. Match the fitting to the original part number shown in your exhaust-system diagram.

When to Replace

• The fitting is cracked, physically damaged, or distorted at the hose connection
• Corrosion has weakened the fitting body or threads
• Leakage occurs around the fitting or at the hose connection
• The fitting is damaged during exhaust elbow removal
• The connected cooling hose no longer seats or clamps securely on the fitting
• The exhaust elbow assembly is being replaced

Inspect the connected cooling hose and clamp whenever the fitting is serviced — replace any hose showing cracking, swelling, or heat damage at the same time.

Installation Notes

• Confirm the 45-degree outlet angle matches the original fitting and hose routing before installation
• Inspect the exhaust elbow for corrosion or damage around the threaded fitting port
• Inspect the mating cooling hose for cracking, swelling, or heat hardening — replace if in doubt
• Replace damaged or aged hose clamps at the same time
• Route the cooling hose without sharp bends or kinks after the fitting is installed
• Follow the applicable MerCruiser service manual for fitting installation, sealing requirements, and torque

Related Components

The following parts appear in the same exhaust elbow and cooling-discharge assemblies on applicable MerCruiser engines:

• 92499 / 22-92499 — superseded by 865159 (same function, earlier part number)
• 866725 — straight exhaust-elbow hose fitting (same elbow, different outlet angle)
• 807988A03 — 7-degree / 4-inch OD exhaust elbow assembly used with this fitting
• 863724 — standard-cooling exhaust elbow gasket
• 8637251 — closed-cooling exhaust elbow gasket
• 863726 — gasket used with exhaust riser kits

Technical FAQ

What is the difference between 865159 and 866725?
865159 has a 45-degree angled outlet and 866725 has a straight outlet. Both attach to the exhaust elbow at the cooling-hose connection, but the outlet angle determines how the hose routes away. These are not interchangeable — use the part number shown in your specific exhaust diagram.

Does 865159 directly replace 92499?
Yes. 865159 / 22-865159 is the current Mercury part number that supersedes 92499 / 22-92499. If your diagram or service history shows 92499, order 865159. The current part may look slightly different from the original but is the factory-approved functional replacement.

Which exhaust elbow does this fit?
This fitting is documented with selected MerCruiser exhaust elbows including the 807988A03 (7-degree / 4-inch OD elbow assembly). However, it appears across a wide range of MerCruiser exhaust configurations — confirm by the diagram for your specific engine and serial number.

Parts Desk Insights

The angle is everything with this fitting — 45 degrees versus straight changes how the cooling hose leaves the elbow, and getting it wrong usually means the hose either kinks or doesn’t reach. The most common ordering mistake is grabbing the straight 866725 because it’s the same elbow, same threads, and the description looks close enough. Check your diagram for the fitting item number before ordering. The other thing we see is the old 92499 number on service records — 865159 is the current replacement and will be what ships; they are the same part under a current number.