Westerbeke Vire 7, Руководство пользователя, Страница: 9 / 43

Installation of Engine and Propeller Shaft
It is extremely important that the propeller shaft and the power take-off shaft (gear box screw
shaft) are completely aligned and centered.
The propeller shaft does not require a special pressure bearing because the screw shaft bearing
absorbs axial loads also. First install the above shafts to align alignment and centering is done by
moving the engine.
Before the final engine installation check, fasten engine to bed but leave gear flange screws
unfastened. The engine is correctly installed when the coupling flanges are completely parallel
and centered. Alignment of flanges is checked by a feeler gauge. If the distance between the
flanges is not the same in all directions, adjustment is made by changing the position of the engine.
After fastening the coupling turn the propeller shaft with the gear lever in neutral position. If the
propeller shaft moves freely and evenly, the installation is correct. If a sternpost tube with a
rubber sleeve mounted front bearing is used, it is important that the propeller shaft front is
carefully centered into the sternpost tube before final inspection. The centering is best achieved
by disconnecting the sleeve, sliding the bearing assembly forward and locating the shaft in the tube
with small wedges.
It is recommended that the engine bed is made so high that thin shims can be placed between the
engine and the engine bed to get the engine installed at the correct height.
If the initial alignment is accomplished during boat construction or while the boat is still on its
cradle, the coupling should be disconnected and all alignment rechecked shortly after launching.
The engine alignment should be rechecked after the boat has been in service for one to three
weeks, and if necessary, the alignment remade. It will usually be found that the engine is no
longer in alignment; this is not because the work was improperly done at first, but because the
boat has taken some time to take its final shape and the engine bed has probably absorbed some
moisture, requiring the removal or addition of shims to keep the engine in its proper position.
Exhaust Pipe and Cooling System
In spite of the cooling through the water casing, exhaust gases from the exhaust collector are still
hot: up to 300
o
C depending on load. If a hot exhaust pipe is not inconvenient it is possible to
A
draw
@
a dry exhaust pipe and lead the cooling water directly from the cylinder and out through
the boat side (Fig. 4.A). Usually a hot exhaust pipe is avoided because of fire hazard and heat
radiation. Figure 4. B shows an exhaust system which is recommended when the cooling water is
led out through the exhaust pipe. The part of the exhaust pipe closest to the exhaust collector
should be raised to a level where seawater cannot enter the engine through the exhaust pipe.
From the highest point the exhaust pipe is further led as shown in figure 4. B.
If the use of a water casing at the raised portion of the exhaust pipe is not desired (as shown in
Fig. 4. B), the cooling water can be led directly to the exhaust pipe at point 1. In this case the
raised part of the exhaust pipe is hot and should be insulated. Since the temperature of the cooled
part of the exhaust pipe does not exceed 100
o
C, a flexible pipe of suitable plastic or rubber
compound can be used (check with supplier).