Cu. In. (3.48cc)
HP @ 25,000
READ ALL SAFETY
INSTRUCTIONS! Failure to read, understand and follow
these instructions could result in personal injury and/or
property damage to yourself or others.
a few moments to familiarize yourself with the various parts
of the engine. DO NOT DISASSEMBLE YOUR ENGINE! Doing so will
void your warranty. No exceptions!
HIGH PERFORMANCE FEATURES
Improvement of former engine P/N 8906 to 8907
SLEEVE: A new feature is a heavier wall brass sleeve made
from a harder and stronger brass alloy. The combination
minimizes distortion during machining as well as at running
temperatures. New machines and a new machining process
on the sleeve bore guarantees a truer and rounder surface.
ADVANCED TECHNOLOGY BALL BEARINGS:
A superior and durable ball bearing has evolved from many
years of R/C car racing. Hard running demands that the
bearing withstand 30,000 plus R.P.M. without shedding the
ball retainers, withstand high temperatures without seizing,
and last... almost forever. To meet these demands, K&B
has developed and produced its own version of the super bearing.
We have equipped your new outboard engine with these bearings.
Besides the extra web braces previously added to the exhaust
flange, the crankcase now sports beefed up mounting lugs in
the shape of web braces. It should be noted here, that
the crankcase has been bored out larger to accept the heavier
well sleeve. Therefore, the new sleeves and crankcase
are not interchangeable with the older version engines.
All other parts are interchangeable.
CONNECTING ROD: In our continued efforts to produce a
better product for you, modeler, we have equipped your engine
with a fully machined con-rod made from high tensile strength
aluminum stock. They are also now bushed at both ends,
and profiled to add strength.
CRANKSHAFT: Our 3.5cc outboard engine is being run at
between 29 000 and 30,000 RPM. As a result, reports
of crankshaft failure surfaced. Therefore, in our effort to
make the engine as (???) proof as possible we have increased
the crankshaft diameter from 12ram to 13ram.
PROPELLER SHAFT ASSEMBLY: The prop shaft assembly and
mating part of the lower end casting are threaded (note: left
hand thread). A secure and long wearing assembly is
the result. The drive cable can now be inspected without
removing the powerhead. Simply unscrew the prop assembly
and pull out the cable.
outboard still boasts another feature, the prop shaft bushings
are of new material that requires nothing but water as a lubricant.
Extended tests have shown that they will last for hours
of running with very little wear.
CLEANING AND LUBRICATING FEATURES: K&B has added two
new features to enhance operating condition and longevity.
A cleaning hole has been added to the front plate to aid in
cleaning the front or top bearing. Simply place an aerosol
can of Liquid Wrench (or similar product) up to the hole and
"back" flush the bearing. Continue to flush the bearing
until you see fresh cleaner come out under the flywheel.
The bearing may also be oiled, in the same manner.
hole for the flex shaft has been added to the lower unit.
It is recommended that each time, before you run the unit,
you lubricate the cable with a mixture of 50% STP and 50%
20-50 weight oil. K&B still recommends that you
continue to remove, inspect, and re-lube the flex cable (using
Lube P/N 8449) on a continued basis.
We recommend after each days running, that you check each
bolt and screw for tightness.
For maximum life of propeller shaft bushing do not operate
engine out of the water for a period of longer than thirty
(30) to forty-five (45) seconds.
PLUGS: This engine is designed to use the long reach glow
plug (K&B P/N 7311).
Propellers are naturally an important factor. Most propellers
that are available on the market need balancing and "cleaning
up". Unbalanced props cause cracks on boat not to mention
robbing your engine of horsepower and your boat of performance.
So, balancing the prop is very important. You can buy
a fixture for checking balance or you can make your own.
To make your own, mount two single edge razor blades, sharp
edges up, parallel to each other and about 1 1/2 inches apart
on a piece of aluminum "U" channel (or make your own "U' channel
out of wood). Make sure the sharp edges are level with
each other and with the table. Slip a length of 3/16
diameter shafting (drill blanks are best) through the prop.
Place the shaft across the razor blades with the prop in between.
The heavy side of the prop will roll to the bottom.
File on this area until the prop is balanced. Do not
file on the concave part of the prop.
up the propeller means to sharpen the leading edges of the
blades and generally sanding, smoothing, and polishing the
We recommend using K&B 1000+ (25% Nitro) or K&B Speed
Fuel (50% Nitro). Fuel must have a minimum of 18% oil
type engine (Aluminum, Brass, Chrome) does not require prolonged
break in periods. However, we do recommend that you
run the engine at a slightly rich needle valve setting for
the first two runs. These runs should be made with
the engine installed on the boat and running in the water
for periods of not less than five (5) minutes each.
Typically, an engine will be ready for continuous full throttle
and a leaner needle valve setting after ten (10) to fifteen
(15) minutes of running.
If the engine is run at a lean needle valve setting during
the break in period, the following may result:
Piston and sleeve will overheat and score.
The connecting rod, crankshaft and wrist pin will overheat
from lack of lubricant and seize, causing the lower con-rod
bushing to spin in the con-rod, or in extreme cases, the bottom
of the con-rod will break, causing damage to the crankcase,
piston and sleeve.
The crankshaft may seize inside the front plate and fracture.
outboard is mounted directly to the transom of your boat.
If you are using an adjustable motor mount, the outboard mounts
to the motor mount and it in turn mounts to the transom.
THE OUTBOARD IN RELATION TO THE BOTTOM OF THE BOAT: First
of all, you must make sure that the transom is square to the
bottom or riding surfaces of your boat hull. A 3 to
4 degree variation is okay. Any more than that will
require a tapered wooden, aluminum, or epoxy putty shim glued
to the stern.
A good start using the prop provided, is to position the
outboard so that the lowest part of the boat are even with
the top of the propeller bushing housing. (The streamline
threaded part of the lower end casting in front of the propeller).
or V BOTTOM HULL:
The starting position for a flat bottom or shallow V bottom
hull is the same as the tunnel hull. On V bottom hulls
with a V greater than 14 degrees, lower the engine approx.
1/8 inch. These settings are approximate and will
vary from hull to hull.
The riding attitude varies between hulls, and since we do
not know which hull you will use, we can only suggest that
you follow the manufacturer's suggestions. Now that
you have decided where to mount your outboard drill the
holes for your motor mount, we suggest that you allow equal
up or down motor mount adjustment
have proven that the cable drive is far superior to the gear
drive. Maintenance is cut down to a minimum. However,
we ask that you occasionally check and lubricate the flex cable.
Check for excess wear and fraying. Do not rotate the engine
by flipping the propeller in a counter-clockwise direction.
Fraying and unwinding may occur. We recommend a good silicone
base lubricant such as K&B marine grease (P/N 8449) for
your outboard as well as other drive units.
deeper you run the propeller in the water, the smaller the
diameter and or pitch must be. Reason: There is more
water surrounding the prop thus more bite and more load on
the engine. Do not overload the engine, as the engine
is more efficient at higher RPM's (18,000 to 22,000), it will
be more dependable if you keep it within that range.
If you want to use a bigger prop, raise the engine.
This allows the prop blades to surface out of the water.
There is less water surrounding the prop, thus, less load
on the engine.
note that the lower unit of your outboard engine has a pressure
tap fitting. Although the use of pressure is not an
absolute necessity, we highly recommend it as it makes for
a smoother and more even run from a full to empty tank of
fuel. You must connect a length of fuel tubing between
tile pressure fitting and the air vent tube on the tank.
VALVE ADJUSTMENT: Assemble the needle valve onto tile
carburetor and turn it clockwise to completely close it.
Turn until it won't go any further but do not force it. Then
turn it counter-clockwise 4 to 4 1/2 turns, if you are running
rear sea level, 3 1/2 to 4 turns at higher altitudes.
As these are only starting settings, you might have to re-adjust
the needle valve to make it the correct setting for your area.
Once you have arrived at a setting, you can lock the
needle valve in place as the carburetor has a built in collet
lock. Turn the black acorn nut clockwise to lock the
needle valve in place, counter-clockwise to loosen.
It takes a 1/4 inch wrench. Only tighten it enough
so that the needle valve cannot be moved. Do not force it.
ADJUSTMENT: Your carburetor has an engine idle adjustment.
It's the screw on top of the carburetor with the spring under
it. If you turn it counter-clockwise, the engine will
idle slower. If you turn it clockwise, the engine will
idle faster. By looking into the carburetor venturi,
you will note that the hole opens and closes as you actuate
the carburetor arm back and forth. Notice the notch
on the one side of the barrel (the moving part with the hole
in it). Turn the idle adjustment screw counter-clockwise
until the notch disappears. This will shut the engine
off completely. With the carburetor linkage installed
and the transnutter throttle and trim set at completely closed
position, (make sure that the carburetor idle is set so that
the notch in tile barrel is not visible), then with the transmitter
trim, open the carburetor so that the notch is now visible
for 1/16 of an inch. This is the starting position.
before, the engine runs in a clockwise rotation. Make
certain that your starter motor is running in the same direction.
With the tank full of fuel and the glow plug battery leads off,
fully open the carburetor and with your finger covering the
carburetor venturi, spin the engine with the starter for about
a two second burst. This primes the engine. Now
close the carburetor to the starting position. Connect
tile GLOW battery and spin the engine again. The engine
should fire up and run. We recommend that you start your
engine close to the water so that you will not have too far
to walk with the engine running with no water circulating through
the cylinder head it is also advised that you keep the engine
at a slow or not greater than a slightly fast idle until you
get into the water, as over revving plus overheating can damage
that you use a fuel filter in your fuel system. Install
the fuel filter on the fuel pickup tubing between the tank and
carburetor. It will keep foreign matter from going into
the carburetor to create clogging. However, the filter
also can clog up. Therefore, should it clog, remove the
filter from the fuel line and clean it as per the manufacturer's
instructions. If you do not have a fuel filter in your
system, there is a chance that foreign matter will find its
way into the carburetor causing your engine to run at a very
lean setting, no matter how much you open the needle valve.
The particles will wedge themselves in between the needle valve
point and the fuel outlet tube (spray bar). The best
way to remove them is by removing the complete needle valve,
lock nut and all. Remove it by unscrewing the brass nut
just next to the black lock acorn nut. This opens up
the fuel chamber inside the carburetor, then blow into this
chamber. This will clear out the spray bar. Replace
the assembly and snug up the brass nut. Check your fuel
and pressure lines frequently for holes or cracks that could
also cause the engine to run lean.
that not everybody will run their outboard in saltwater.
Those of you that will, however, should heed the following
is a must to take a can of spray lube with you when saltwater
racing. Before and after each run, spray all metal
hardware on your boat (this includes the engine) with spray
lube. At the end of the day's running, remove the
glow plug and by spinning the engine through with the starter,
flush at least two ounces of fuel through the engine by
holding your finger over the venturi. Then, pour a
good amount of spray lube oil into the venturi and spin
the engine again for a short spurt. Flush the rest
of the outboard and boat with lots of fresh water.
Spray lube all moving parts, and threads on screws. Also
flush the bearings and lower unit as described in the beginning
of this manual.
Model Engine Corporation of America, All rights reserved.
K&B and the oval logo are Registered Trademarks of Model Engine
Corp. of America
Registered U.S. Patent Office
part may be reproduced without written permission from
MECOA/K&B -- P.O. Box 5 -- Sierra Madre, CA 91025 U.S.A.