Zero Speed Detent - Hamilton Jet HJ212 Installation And Service Manual

Installation

Zero Speed Detent

Refer to drawing: HJ21207003 Reverse Assembly.
A detent is provided to indicate the zero speed position at the control lever.
Unlike conventional propulsion systems using gearboxes, the waterjet does not have a
positive neutral, instead relying on the position of the reverse duct to provide neutral (zero
speed).
The zero speed detent is the only way the operator has of knowing whether the reverse duct
is in the zero speed position.
Proper selection of zero speed prior to start-up, is essential for safe start-up and
manoeuvring.
Detent zero speed position adjustment
Launch the vessel on a calm day away from wind and currents. Start the engine, put the steering in the

straight ahead position and operate the reverse control lever until the craft is holding position.
Loosen the brake rod nut [55]. If the left hand drive cable mount [57] is installed, then the nuts [55]

securing it will also need to be loosened.
Screw the break rod [41] either in or out until the detent groove locates in the detent plate. The brake

plates [46] may need to be released to allow the rod to turn.
In general, zero speed is achieved when the bottom lip of the reverse duct sits 1/3rd of the
way up the nozzle outlet.
The zero speed position will change if the nozzle is tilted, this amounts to about 8mm of
movement on the brake rod.
There is at approximately 20mm of adjustment in the brake rod to accommodate both nozzle
positions.
Once the detent corresponds to zero boat speed, tighten the brake rod nut and if fitted, the left hand

drive installation nuts.
Check the zero speed position by manoeuvring the vessel in calm conditions.

Adjustment of the detent strength
The strength of the detent is factory set and should not need adjustment. If however, adjustment is required:
Record the position of the zero speed detent groove in the brake rod.

Loosen the brake rod nut [55] that prevents rotation of the brake rod [41] in the brake rod end piece

[26]. If the left hand drive cable mount [57] is installed, then the nuts [55] securing it will also require
loosening.
Remove the brake rod [41] by unscrewing it from the brake rod end piece [26], and withdrawing it out of

the latch to the port side of the vessel. The latch plates [46] may need to be released by hand to carry
out this operation.
Bend the detent plate [23] to increase or decrease detent pressure as required.

Ensure the screw [43] remains secure.

Reassemble the brake rod [41] and latch assembly. Ensure that the brake rod is reinserted the correct

way round; the detent groove should be nearer the left side of the vessel.
Reset the zero speed position of the detent as described above.

Zero speed detent
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Installation and Service Manual