12
BASIC ENGINE PARTS
Outer Head
Crankcase
Mounting Lugs
Exhaust
Cover Plate
Carburetor
Type 21J2(B)
Crankshaft
Crankshaft Ball Bearing (Front)
13
CARBURETOR CONTROLS
The Needle-Valve(Adjusted at the factory):
The Mixture Control Valve:
Four adjustable controls are provided on
this carburetor.
For adjusting the mixture strength when the
throttle is fully open.
For changing the mixture strength at mid
speed and acceleration. (Do not rotate the
screw more chan one turn.)
The Throttle Stop Screw
(Adjusted at the factory):
For setting the minimum idle speed:
For adjusting the mixture strength at part-
throttle and idle speed, to obtain steady
idling and smooth acceleration to mid speed.
The Metering Needle:
NOTE: Readjustment may be necessary,
occasionally to allow for changes in fuel
formula, gear ratio or clutch engagement
point.
Metering Needle
Throttle Stop
Screw
Mixture Control Valve
Needle Valve
Thermo Insulator
Carburetor Reducer
Ball Link
Dust Cover
14
GLOWPLUG
The role of the glowplug
Glowplug life
Particularly in the case of very high performance
engines, glowplugs must be regarded as expendable
items. However, plug life can be extended and engine
performance maintained by careful use, i.e.:
Install a plug suitable for the engine.
Use fuel containing a moderate percentage of
nitromethane unless more is essential for racing events.
Do not run the engine too lean and do not leave the
battery connected while adjusting the needle.
With a glowplug engine, ignition is initiated by the
application of a 1.5-volt power source. When the
battery is disconnected, the heat retained within the
combustion chamber remains sufficient to keep the
plug filament glowing, thereby continuing to keep the
engine running. Ignition timing is 'automatic' : under
reduced load, allowing higher rpm, the plug becomes
hotter and, appropriately, fires the fuel/air charge
earlier; conversely, at reduced rpm, the plug become
cooler and ignition is retarded.
Apart from when actually burned out, a plug may
need to be replaced because it no longer delivers its
best performance, such as when:
When to replace the glowplug
Filament surface has roughened and turned white.
Filament coil has become distorted.
Foreign matter has adhered to filament or plug
body has corroded.
Engine tends to cut out when idling.
Starting qualities deteriorate.
Since the compatibility of glowplug and
fuel may have a marked effect on
performance and reliability, it may be
worthwhile to choose the R/C type plug
found most suitable after tests.
Recommended O.S. plugs are P3, P4 and P5.
Carefully install plug finger-tight, before
final tightening with the correct size plug
wrench.
15
7mm
Install the exhaust seal ring supplied.
Exhaust
Seal Ring
Glowplug
INSTALLATION OF THE DUST CAP SET
If the engine is to be stored or out of use for a while,
install the included exhaust and carburetor dust caps
to prevent foreign matter from entering the engine.
INSTALLATION OF THE STANDARD ACCESSORIES
Installing the glow plug. Insert P3 plug supplied
into heatsink-head carefully, making sure that
it is not cross-threaded before tightening firmly.
(All the O.S. T-Type plugs including the P3 are
not supplied with a washer.)
Installing the carburetor reducer
Replace the reducer according to the course
conditions.
Supplied with the engine.
Standard with the carburetor when it leaves the
factory.
6mm
6.5mm
Carburetor Controls
Glowplug
16
INSTALLATION OF THE CARBURETOR
As delivered, the engine has its carburetor lightly
installed in the intake boss. Secure it as follows.
Loosen the retainer screw, rotate the
carburetor to its correct position and make
sure that it is pressed well down into the
intake boss, compressing the rubber gasket,
before retightening screw.
1.
2.
Rotate the retainer nut
gently until it stops.
Tighten a further
120-180
Rotate the retainer screw gently until it
stops, then tighten a further 120-180 .
Do not overtighten the screw as this will
damage the carburetor body.
Note
Be careful not to damage the O rings when
removing the carburetor retainer from the
engine.
First, remove the retainer Retaining screw,
then pull out each part. Do not push the
part in or damage the O rings.
Retaining Screw
"O" Ring
"O" Ring
17
ENGINE INSTALLATION
Chamfer inside edges of bearers.
Do not allow bottom
of crankcase to
touch chassis.
Make sure that the vehicle's engine mounting
surfaces are level and in the same plane. Poor
installation may cause distortion of the
crankcase, bearings, etc., resulting in erratic
running and loss of performance.
The recommended screws for securing the
engine are 3mm or 4-40 steel Allen hexagon
socket type. If existing holes in the engine mount
do not align perfectly with engine mounting lugs,
enlarge them slightly with a needle-file so that
screws are in alignment with the mounting holes.
Note:
Be sure to use a collet supplied when use a
optional 28XZ Hyper Flywheel Set.
The engine bottom may interfere with chassis
of some models. In this case, file off the
chassis so that the engine may not interfere
with the chassis when it is installed.
NOTE
Carb Installation