Hamilton Jet HJ241, Manual

Page: 51 / 202

3.17
3 DESIGN BASICS
3.8 D
ESCRIPTION OF THE
D
RY
R
UN
S
YSTEM
(O
PTIONAL
E
XTRA
)
HJ-241 / HSRX
3.8 DESCRIPTION OF THE DRY
RUN SYSTEM (OPTIONAL
EXTRA)
NOTE: Hamilton Jet Units are not fitted with the Dry
Run Kit as a standard fit. The Dry Run Kit
is an optional extra which can be fitted to the
Jet Unit at the customers request. Should the
customer require a Dry Run System fitted, it
can be purchased at additional cost and
should be requested when the Initial Jet Order
is placed.
The Dry Run System is a simple solution to the
problem of starting a boat engine before putting the
vessel in the water. It is particularly useful fo Man-
Overboard boats and Lifeboats where it is important
to ensure that the engine will start before the vessel
is in the water.
The Dry Run Kit consists of a specially formulated
Marine Bearing which can be run dry for short
periods and run for long periods with water
lubrication. The standard rubber Marine Bearings
are designed to run in a water immersed
environment where the water acts as a coolant and
lubricant for the Bearing and Water Seal. These
cannot be run out of water.
3.8.1 Installation
The Dry Run Bearing components are a direct
replacement for the standard Marine Bearing
components, therefore there is no requirement for a
special installation procedure for converting a Jet
Unit to the Dry Run System. The Dry Run Bearing
components can be fitted as shown for the normal
Marine Bearing replacement in the Jet Unit Manual.
3.8.2 Corrosion
All the components of the Dry Run Kit are made of
high quality corrosion resistant materials. The
plastic Bearing will turn slightly blue / green after
being immersed in sea water,. This is only a surface
discolouration and is not detrimental to the
performance of the Dry Run Kit System.
3.8.3 Scope of Use
Because there is no cooling for the Dry Run System
Marine Bearing, if a Jet Unit is run without the vessel
being immersed in water, with no water to act as a
coolant, the Marine Bearing will heat up rapidly.
THE FOLLOWING LIMITS MUST BE ADHERED TO,
TO ENSURE GOOD COMPONENT LIFE.
The plastic Dry Run Kit Bearing is a compromise for
use in both dry and wet running conditions. The
best wet running design solution is the use of a
rubber Marine Bearing which cannot be run dry.
The plastic Dry Run Kit Bearing will wear out far
quicker than a standard rubber Marine Bearing if the
dry run system is used constantly in a dirty water
environment. When used in silty water, the life of
the bearing and sleeve will be reduced, depending
on the volume of grit in the water.
THIS SYSTEM
SHOULD ONLY BE USED IN A CLEAN WATER
ENVIRONMENT
.
If extended use in a dirty water environment is
expected, then regular monitoring of Marine Bearing
wear is required.
Maximum Dry Run Time 3 Minutes.
Maximum Dry Run Engine
Speed: 1000 RPM.
Minimum Time Between Dry
Runs: 1 Hour.