850423 Mercruiser VENTURI

At operating temperature, the engine cooling system is hot and under pressure. Steam can cause personal injury. Check the coolant level only after the engine has been stopped and the fill cap on the radiator is cool enough to touch with your bare hand. Remove the fill cap slowly to relieve pressure. Cooling system conditioner contains alkali. Avoid contact with skin and eyes to prevent personal injury.
Hot oil and components can cause personal injury. Do not allow hot oil or components to contact the skin. Be sure that the engine and components are cool enough to touch with your bare hand prior to performing any service work.
2. Drain the coolant from the cooling system at elbow (3) below the engine into a suitable container for storage or disposal. Drain the engine oil at drain (1) into a suitable container for storage or disposal.3. Disconnect hose assembly (2) at the drain. 4. Remove ground wire (4) from the disconnect switch.5. Remove electrical wire (5) from the disconnect switch.6. Remove two bolts (6) from the disconnect switch bracket that holds it to the support bracket.7. Close fuel shut-off valve (7) and remove fuel line (8). 8. Remove fuel tank sending unit wire harness clips (9) from rear of the fuel tank. 9. Remove five wiring harness clips (10). One of the wiring harness clips is located on the bottom right side of the fuel tank. 10. Remove bolts (11) from the fuel tank and the support bracket. One on each side of the fuel tank.11. Remove four nuts, and washers (12) from the fuel tank. Two on each side of the fuel tank. 12. Remove hose (13) and hose (14) from the fuel tank.13. Remove three bolts (15) and the support brackets from each side of the fuel tank. 14. Remove nuts (16) and magnetic switch assembly (17) (start relay) from the fuel tank.15. Remove bolt (18) (not shown) and clip for the wiring harness from the bottom of the fuel tank.16. Remove machine screws (19) and circuit breaker (20) from the fuel tank.17. Remove nuts (21) and magnetic switch assembly (22) (main power relay) from the fuel tank. 18. Fasten a hoist and lifting device to the fuel tank as shown. Remove the bolts and the fuel tank from the frame. 19. Disconnect two wire harnesses (23) at the mounting bracket.20. Remove ground wires (24) from the electric starting motor. 21. Remove bolts (26) and washers from dash assembly (25). One of the bolts is on the right side of the machine, The other is on the left side of the machine. Remove dash assembly (25) from the mounting brackets. 22. Remove bolts (27) for the air conditioner compressor. Position the air conditioner compressor to the side.23. Remove six bolts (28) and cover (29) from the throttle control housing. 24. Loosen nut (33) from the throttle control linkage and slide nut (33) up the cable end.25. Remove bolt (30) from the throttle control linkage.26. Remove nut (31) and end (32) from the throttle control linkage.27. Remove the throttle control linkage from the throttle control housing. Do not remove air lines until air pressure is to zero. Personal injury could result if the air pressure is not released.28. Release the pressure in the air system by opening the two valves on the bottom of the air tank. The air tank is located behind the rear bumper. 29. Remove air line (35) from the air compressor.30. Remove air lines (34) from the air compressor. 31. Remove bolts (36) from each side of guards (37). Remove guards (37). 32. Remove bolts (38) that secures pump group drive shaft (39) to the yoke on the hydraulic pump.33. Remove bolts (40) that holds pump group drive shaft (39) to the yoke on the engine.34. Remove pump group drive shaft (39). 35. Loosen clamp (44). Remove hose assembly (43) from the tube assembly.36. Loosen clamps (42) and disconnect heater hoses (41) from the water pump. 37. Attach Tooling (A) and a hoist to the lifting lugs on the engine. 38. Remove bolts (45) and washers from the flange on the transmission. 39. Remove mounting bolts (46) and washers from the front engine mounts.40. Raise the hoist slightly in order to separate the engine flywheel housing from the transmission. Disengage the splined shaft on the transmission from the torsion coupler on the engine. Carefully remove the engine from the machine. The weight of the engine is 1135 Kg (2500 lb).Install Engine
1. Clean all components of the engine and mating components before you install the engine. Check the condition of all O-ring seals used in the hose assemblies that were disconnected. If any of the O-ring seals are damaged, use new parts for replacement.2. Attach Tooling (A) and a hoist to the lifting lugs on the engine. Use Tooling (A) to position the engine to the transmission. The splined shaft on the transmission must be aligned with the torsion coupling on the engine. 3. Install bolts (45) and washers to the flange in order to secure the engine to the transmission. 4. Install mounting bolts (46) and washers to the front engine mounts. 5. Install heater hoses (41) to the fittings. Tighten clamps (42).6. Position hose assembly (43) to its original location. Tighten clamp (44). 7. Install pump group drive shaft (39).8. Install bolts (38) that secures pump group drive shaft (39) to the yoke on the hydraulic pump. Tighten bolts (38).9. Install bolts (40) that holds pump group drive shaft (39) to the yoke on the engine. Tighten bolts (40). 10. Install two guard halves (37) to the implement pump drive shaft.11. Install bolts (36) to secure the guard to the mounting and the two halves together. The bolts that hold the guard to the mounting must be tightened to a torque of 135 20 N m (100 15 lb ft). 12. Install air line (35) to the air compressor.13. Install air lines (34) to the air compressor. 14. Slide nut (33) on the