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90-10240040 DECEMBER 2003
250 HP Jet Drive Installation Manual
NOTICE to COMMISSIONING DEALER
Pre-delivery Preparation Instructions Must Be Performed Before Delivering Boat to the Product Owner.
NOTICE to INSTALLER
After Completing Installation, These Instructions Should Be Placed with the Product for the Owner’s Future Use.
NOTICE to INSTALLER
The United States Coast Guard does not have a method to determine the maximum recommended horse-
power for Inboard Jet Boats. Therefore, it is the responsibility of the boat manufacturer to install the Mercury
Jet Drive, as well as any other Jet Drive model, in a boat which has been determined to be of suitable size,
weight, construction, and hull configuration for the power chosen. The Mercury
Jet Drive, in particular, brings
a new level of performance to the jet boat category and is capable of propelling many hulls at speeds exceed-
ing 50 miles per hour.
In selecting the proper Jet Drive package for a particular application, please consider the overall performance
capability of the craft. Your boat may react to and handle differently with each Jet Drive model.
PLEASE carefully test and evaluate the overall handling characteristics of the boat package before
distribution for sale.
If you have application or installation questions, please contact your Mercury Marine OEM Sales Coordinator.
The Sales Coordinator will arrange to provide the necessary assistance.
Please assess your boat’s performance completely before making the Jet Drive model selection.
Safe boat-
ing is good for everyone.
Table of Contents
General Information 2. . . . . . . . . . . . . . . . . . . . . . . . . .
Notice to Installer 2. . . . . . . . . . . . . . . . . . . . . . . . . .
Torque Specifications 3. . . . . . . . . . . . . . . . . . . . . .
Installation Requirements 3. . . . . . . . . . . . . . . . . . . . .
Battery/Battery Cables 3. . . . . . . . . . . . . . . . . . . . .
Boat Construction 4. . . . . . . . . . . . . . . . . . . . . . . . .
Engine Compartment Ventilation 4. . . . . . . . . . . .
Exhaust System 4. . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel Delivery System 5. . . . . . . . . . . . . . . . . . . . . .
Instrumentation 6. . . . . . . . . . . . . . . . . . . . . . . . . . .
Remote Control and Cables 7. . . . . . . . . . . . . . . .
Steering Helm and Cable 8. . . . . . . . . . . . . . . . . . .
Wiring Diagram 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Quicksilver Instrumentation,
Typical Analog Installation Shown 9. . . . . . . . . . .
Wiring for SmartCraft Gauges 10. . . . . . . . . . . . . . . . .
Wiring Connections to Paddle Wheel Speed
Sensor, Oil Tank and Fuel Tank 10. . . . . . . . . . . .
Typical System Layouts – Single Engine
Product Configurations 11. . . . . . . . . . . . . . . . . . . .
Wiring Information for CAN Type Gauges 12. . . .
Wiring Accessories for CAN Type Gauges 13. . .
Typical Installation Configurations
for CAN Type Gauges 14. . . . . . . . . . . . . . . . . . . . .
Mercury Jet Drive Hull Dimensions 15. . . . . . . . . . . .
Hull Opening 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installing Jet Pump 16. . . . . . . . . . . . . . . . . . . . . . . . . .
Steering Cable Adjustment 20. . . . . . . . . . . . . . . . . . .
Shift Cable Adjustment 23. . . . . . . . . . . . . . . . . . . . . . .
Installing Powerhead 27. . . . . . . . . . . . . . . . . . . . . . . .
Fuel Line and Fuel Vapor Vent Hose Connections 28.
Battery Cable and Remote Wiring Harness
Connections 29. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Throttle Cable Installation 30. . . . . . . . . . . . . . . . . . . .
Oil Injection Set-Up 31. . . . . . . . . . . . . . . . . . . . . . . . . .
Bilge Siphon Feature 33. . . . . . . . . . . . . . . . . . . . . . . .
Water By-Pass System 34. . . . . . . . . . . . . . . . . . . . . . .
Installation of Flushing Kit 36. . . . . . . . . . . . . . . . . . . .
Flushing Instructions 38. . . . . . . . . . . . . . . . . . . . . .
Suggested Flushing Intervals 38. . . . . . . . . . . . . .
Trim Plate Adjustment 39. . . . . . . . . . . . . . . . . . . . . . .
Exhaust System Installation 40. . . . . . . . . . . . . . . . . .
General Exhaust System Notes 40. . . . . . . . . . . .
Exhaust Outlet Measurement Procedure 40. . . .
Top View 41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Aft View 42. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Side View 43. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Side View of Expansion Chamber Outlet
Pipe and Exhaust Pipe Connection 44. . . . . . . . .
Pre-delivery Inspection 45. . . . . . . . . . . . . . . . . . . . . . .
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