816163 Mercruiser THERMOSTAT

At operating temperature, the engine coolant is hot and under pressure. Steam can cause personal injury. Drain the coolant only after the engine has been stopped and the fill cap is cool enough to touch with your bare hand. Remove the fill cap from the radiator slowly to relieve pressure. Cooling system conditioner contains alkali. Avoid contact with the skin and eyes to avoid personal injury.
1. Drain the coolant from the cooling system.
Typical Example2. Disconnect two tube assemblies (4) from the regulator housing. Remove the O-ring seals.3. Loosen the clamps that hold tube (3) to the regulator housing. Move the tube away from the regulator housing.4. Remove bolts (1) and move tube (2) away from the housing.
Typical Example5. Mark the wires for identification. Disconnect the wires from switches (7), (8) and (10).6. Remove the bolt and clamp that holds wire harness (9) to the regulator housing.7. Remove the bolts and retainers that hold tube (5) in place in the regulator housing and water pump. Remove the tube.8. Fasten a hoist and tool (A) to regulator housing (6). Remove bolts (11) and the bolts that hold the regulator housings to the brackets. Remove the regulator housings from the engine. The weight of the regulator housings is 37 kg (81 lb).
Typical Example.9. Put the regulator housing in the position shown. Remove bolts (12), and separate the regulator housings. 10. Remove water temperature regulators (13) from the regulator housing. 11. Remove seals (14) and ferrule (15) from the regulator housing. Remove the ball from under ferrule (15). The following steps are for installation of the water temperature regulators. 12. Install the ball and ferrule (15) in the regulator housing. Make sure the open end of the ferrule is toward the outside of the housing. Ferrule (15) must make contact with the bottom of the bore.13. Install new seals in the housing with tool (B). Install the seals with the lip toward the inside of the regulator housing.
If the water temperature regulators are installed wrong, it will cause the engine to overheat.
14. Install water temperature regulators (13) in the regulator housing with the spring up as shown.15. Fasten a hoist and tool (A) to the housing. Put the gasket and housing in position on regulator housing (6), and install the bolts that hold them in place.16. Fasten a hoist and tooling (A) to regulator housing (6). Put the regulator housing and the gaskets in position, and install bolts (11) and the bolts that hold the regulator housings to the brackets.17. Install the clamps and bolts that hold tube assembly (5) to the regulator housing.18. Connect wires (7), (8) and (10) to their proper switches.19. Make sure the O-ring seals are in position on each end of tube (5). Put clean oil on the O-ring seals. Put tube (5) in position in the water pump and regulator housing. Install the retainers and bolts to hold it in place.20. Install the clamp and bolt that holds wire harness (9) to the regulator housing.21. Install the O-ring seals. Connect two tube assemblies (4) to the regulator housing.22. Connect tube assembly (3).23. Put tube (2) in position on the regulator housing and install clamps and bolts (1) to hold it in place.24. Fill the cooling system with coolant to the correct level. See the Maintenance Manual.