Main Components - Hamilton Jet HJ212 Installation And Service Manual

Installation and Service Manual

Main Components

Intake block
Is bolted or welded to the vessel hull.
Intake
Is bolted to the intake block and represents the main structural body of the jet unit. It is capable of
transmitting the full thrust of the jet unit to the hull bottom. The intake is cast from high silicon aluminium
alloy.
Thrust bearing
Mounted inside the bearing housing, absorbs the thrust generated by the impeller.

No external thrust bearing is required.

Water seal
Mounted on the mainshaft aft of the bearing housing. Stops water entering the bearing housing or the

vessel.
Coupling
The jet unit can be connected to various engine types using the following:
Close coupling to certain gasoline engines.

H-bar connection to the jet mainshaft splines.

Companion flange fitted to the jet mainshaft splines, where a longer driveshaft is required.

Engine mount and close coupling
This jet is designed with the option of a flexible close coupling arrangement combined with an engine mount.
This allows the engine to be moved as far aft as possible in the boat, simplifying the driveline arrangement
and providing a low noise torsionally flexible coupling.
Impeller
Mixed flow type, capable of pumping large volumes of water at relatively low pressures. Permits high
propulsive coefficients to be achieved at fast vessel speeds. The cast stainless steel impeller runs within a
replaceable stainless steel wear ring located in the rear section of the intake.
Tailpipe
The tailpipe contains a water lubricated bearing supporting the rear of the mainshaft.

The tailpipe contains a vaned stator to remove the rotation of the water flow, allowing a uniform axial

flow to the nozzle.
Steering nozzle
After the water flow passes through the impeller and stator, it is at a high pressure and relatively low

velocity.
Water flow at the nozzle outlet is at atmospheric pressure. This difference in flow pressure is converted

to flow velocity in the nozzle.
Correct nozzle sizing is critical to the correct operation of the jet unit.

2-3
Product Description