18-3638 Outboard Thermostat for Mercury Mariner | JLM Marine family-mercury-850hp Remove the bolts securing the

Remove the bolts securing the housing using the appropriate socket

Thoroughly clean the mounting area on the transom shield to ensure a clean surface for a proper seal

All components manufactured to OEM specifications for reliable fitment and durability

Reinstall any retaining clips or fasteners to secure the new cap guide firmly in place

Reconnect the battery and operate the trim/tilt system through its full range of motion several times

18-3638 Outboard Thermostat for Mercury Mariner | JLM Marine family-mercury-850hp Remove the bolts securing theThermostat for Mercury Mariner Outboard Fits 2. 5 6 HP Models This high quality aftermarket thermostat is engineered to fit Mercury Mariner 2 stroke outboard engines ranging from 2. 5 HP to 6 HP. Designed as a direct replacement for OEM part numbers 804540 and 853704, it ensures reliable temperature regulation for your outboard motor. The kit includes both the thermostat and a rubber seal ring, providing everything needed for a complete installation.