|Sparkplug to transom with
Zenoah should be close to 540mm (transom is the vertical part of the back
of the boat). Fit the engine to the complete rubber mount assembly and
position it where shown but do not fix in place yet. Remove the pullstart
from the motor and remove the 3 countersunk screws which fix the big
aluminium plate to the motor. The screws may be tough to remove.
Take out both screws from the red coil and loosely fit the coil relocator
using the same screws. Turn the flywheel until the magnets are on the
opposite side to the coil ( magnets are the shiny metal parts on the
outside of the flywheel). Push the coil away from the flywheel and put a
piece of thin card between the coil and flwheel. Press down on the red
coil and tighten the 2 screws and then remove the cardboard. This will set
the correct airgap between the coil and flywheel. Fix the motor mount
brackets to the engine and fit the throttle bellcrank and/or bracket to
the front of the motor as shown in the pictures. Fit the pullstart
using the M4 screws in the motor mount kit. Before fitting the pullstart
make sure the screws do not bottom out. If they do then use some shorter
screws or washers under the heads of the bolts. Bolt the rubbers to the
brackets using the nuts and washers provided. The motor mount and rubbers
will then fit between the wooden rails. Fit the coupling to the motor.
The strut and rudder should now be mounted on the
transom of the boat in the position shown in the drawing and picture.
Drill a hole for the proptube in the ‘V’ of the transom and elongate
it upwards with a file so that the strut height can be varied. After first
tests to find the best strut height/propeller the tube exit through the
transom can be with silicone sealer although many people leave this
hole open. Fit the tube is the next job . The tube should run along
inside the bottom of the boat and it should make a gentle curve up
to the motor. The tube will bend without kinking if bent carefully.
Cut the prop tube to length so that it is about 10 to 15mm from the
coupling but pushed into the strut as far as possible. The tube should run
along the bottom of the hull from the transom and then be curved upward to
slide into the coupling. The front end of the tube near the engine
must be supported.
End of strut or stinger should be between 65mm and 100mm. We like
to run it between 65 to 80mm but its not critical on the Sigma. The front end of the
tube near the engine must be supported by the T- bar as shown in the pics.
not fix the tube near the transom or it will be
impossible to adjust the strut height or angle. Cut the flexi to length, remembering to leave a gap of 5 to 6mm (not less
than 5mm) between thrust washer and the strut. Do not cut the flexi too
short, because it has to go inside the coupling as far as possible. The
collet in the coupling may be closed up, if so then open each slit with a
knife blade or something similar. When the collet coupling is tightened
onto the shaft, use a lot of force. The fuel tank must be fitted behind
and to the right side the engine, i.e between engine and radio box. Racers will have their own ideas but keep the tank as far back as possible
in the boat. The flexi
should slide smoothly into the coupling, to be sure of correct alignment.
Fix the mounting feet in position with fibreglass paste. This can be
reinforced with fibreglass mat or tape if required. The inside of the deck
hatch opening at the front of the deck should be cut back until the hatch
fits into it. Fix the hatch down using GA8 hatch fasteners or similar at
the rear. At the front of the hatch, trim the projecting part so that it
slides easily under the deck. This part may need reinforcing with glass
cloth and epoxy. The radio box can be fibreglassed in place or fixed to
the rails with brackets. Take care to seal any holes in the radio box with
cyano, epoxy or silicone (preferably cyano or epoxy). A standard size
metal geared high torque rudder servo of at least 9kg but preferably 13 kg
torque should be fitted on its side on a strong servo mount of aluminium
or carbon angle. The throttle servo can be any standard or high speed
standard size or small size. Use a 5 cell Nimh or nicad pack for the
Balance point of 460mm from the transom
without fuel is critical. Do not be afraid to add some weight to the front
of the boat to achieve this.
Turn fins should be fitted at 90
degrees to the hull bottom on each side as close to the outside edge as
possible. Make sure the brackets and turn fin are very strong. Movement in
this area will affect the turning of the hull.
The trim of the hull can be altered by trim tabs, strut height or angle and
rudder position. The boat will be fastest with a strut but if a stinger is
used it is recommended not to use the larger stingers such as Top
The flexi shaft MUST be removed and greased
after every days running. Mercury Quicksilver grease is popular but any
grease is sufficient.
Only use balanced / sharpened propellers.
Using the CS23A long tuned pipe and 100 degree manifold and fix the rear
of the tuned pipe with a stainless hose clip and aluminium bracket. Pipe
length from exhaust flange on the engine to widest part of tuned pipe
should be 330 to 345mm. Start at 345mm and shorten to get more rpm.
Take care to range check
the radio before use.
For Zenoahs and other petrol engines use
1/4" flexi with 1/4" stubshaft. With the kit supplied prop the
boat will be capable of 55 to 57 mph. For highest speed buy one of our
special modded propshop props. To attain the highest speeds will take some
time in adjustment of strut or stinger height and angle. If you are racing
the boat then keep checking this website page as I will be producing additional
or replacement items to aid boat stability and speed and will provide full
trimming and running instructions.