O.S. engine FL-70 Setup guide

FL-70
FOUR CYCLEENGINE
OWNER'SINSTRUCTIONMANUAL
Itisof vitalimportance, beforeattempting to
operateyourengine, toreadthe general
•SAFETYINSTRUCTIONS AND WARNINGS'
section on pages 2-6 of this booklet and to strictly
adhere to the advice contained therein.
•Also, pleasestudy the entire contents of this
instruction manual, so as to familiarize yourself
with the controls and other features of the
engine.
•Keepthese instructions ina safe placeso that
you may readily refer to them whenever
necessary.
•Itissuggested thatanyinstructionssupplied
with the aircraft, radiocontrol equipment, etc.,
are accessible for checking atthe sametime.

CONTENTS
SAFETY INSTRUCTIONS AND WARNINGS
ABOUT YOUR O.S. ENGINE ---------------- 2-6
ENGINECONSTRUCTION ------------------------7
NOTESWHEN APPLYING AN ELECTTRICSTARTER ---- 8
INTRODUCTION -------------------------- 9
BEFORESTARTING ---------------------- 10-13
ENGINE PARTS NAME--------------------------------------14
INSTALLATION ------------------------------------------------ 15-16
SILENCER& EXHAUSTHEADERPIPEINSTALLATION------- 17
FUEL TANK & LINES -------------------------------- 18-20
THROTTLELINKAGE,NEEDLE-VALVE EXTENSION ------ 21
PROPELLER& SPINNERATTACHMENT---- 22-23
GLOWPLUG -------------------------------------------24
TYPE 60WCARBURETOR, STARTING --------25-27
RUNNING-IN, CARBURETOR -------------------- 27-30
CARBURETOR AIR-BLEED ADJUSTMENT-------- 31
TROUBLE SHOOTING WHEN THE
ENGINE FAILS TOSTART----------------------- 32-33
VALVE ADJUSTING -------------------------------- 34
HOWTOSETTHE CAMSHAFT TIMING --------- 35
CARE AND MAINTENANCE ----------------------- 36-37
ENGINEEXPLODEDVIEWS&PARTSLIST--------38-39
CARBURETOR EXPLODED VIEWS
&PARTS LIST ---------------------------------------- 40-41
GENUINEPARTS & ACCESSORIES -------42-43
THREE VIEW DRAWING --------------------------------- 44
1

SAFETY INSTRUCTIONS AND WARNINGS ABOUTYOUR O.S.ENGINE
Remember that your engineisnota "toy",buta highly efficient internal-
combustion machinewhosepoweriscapableof harmingyou,orothers,ifitis
misused.
As owner, you, alone, are responsible for the safe operation of your engine, so act
with discretion and care at alltimes.
Ifat some future date, your O.S.engine is acquired byanother person, we would
respectfully request that these instructions are also passed onto its new owner.
The advice which follows isgrouped undertwo headings according to the
degree of damage ordanger which mightarise through misuse orneglect.
WARNINGS
These cover events which
might involveserious(in
extremecircumstances,even
fatal)injury.
NOTES
These cover the many other
possibilities, generally lessobvious
sources of danger, butwhich, under
certain circumstances, may also
causedamage orinjury.
2

WARNINGS
Model engine fuelisalso highly
flammable.Keepitawayfromopenflame,
excessive heat, sources of sparks, or
anything else which might
igniteit.Donotsmoke or allow
anyoneelsetosmoke,neartoit.
Aweakened orloose propellermay
disintegrate orbethrown off and,since
propeller tip speeds with powerful
enginesmayexceed600feet(180metres)
persecond, itwill beunderstood that
such a failure could result inserious
injury, (see'NOTES' section relatingto
propellersafety).
Nevertouch, or allow any object to come
intocontact with, the rotating
propeller anddo notcrouch
over the enginewhen itis
running.
Neveroperate your engineinanen-
closed space. Modelengines,likeauto-
mobileengines,exhaust deadlycarbon-
monoxide. Run your engineonlyinan
openarea.
Modelengines generate considerable
heat.Donottouch anypart of your
engineuntilithas cooled. Contactwith
the muffler (silencer),
cylinder head orexhaust
header pipe, inparticular,
may resultina serious burn.
Modelenginefuel ispoisonous. Donot
allow itto come intocontactwiththeeyes
ormouth.Alwaysstoreitina
clearlymarkedcontainerand
out of the reach ofchildren.
3

NOTES
This engine was designed for model
aircraft. Donotattempt to useitforany
otherpurpose.
Mount the engine inyour model securely,
following the manufacturers' recommenda-
tions,usingappropriate screws andlock-
nuts.
Besure to use the silencer (muffler)
suppliedwiththe engine. Frequent
exposureto an openexhaust may
eventually impairyour hearing.
Such noise isalso likelyto cause
annoyance to others over a wide area.
Ifyou remove the glowplug from the engine
andcheck its condition by connecting the
battery leads to it, do not hold the plug with
bare fingers.Use anappropriate tool or a
folded piece of cloth.
Installa top-quality propeller of the
diameter and pitch specified for the engine
and aircraft. Locate the propeller onthe
shaft so that the curved face of the blades
faces forward-i.e. inthe direction of flight.
Firmly tighten the propellernut,usingthe
correct size wrench.
4

NOTES
Always check the tightness of the propeller
nutand retighten it,if necessary, before
restarting the engine, particularly inthe
case of four-stroke-cycleengines. Ifa
safetylocknut assembly isprovided with
your engine, always use it. This will prevent
the propeller fromflying off inthe event ofa
"backfire",even if itloosens. Also, check
the tightness of allthe screwsandnuts
before restarting the engine.
Ifyou install a spinner, make sure that itis
aprecisionmade productand that the
slots forthe propellerblades donotcut into
the blade roots and weaken them.
Preferably,use an electric starter.The
wearing of safety glassesisalso strongly
recommended.
Discard any propellerwhich has become
split, cracked, nicked or otherwise rendered
unsafe. Neverattempt to repair such a
propeller:destroy it.Donotmodifya propeller
inanyway, unlessyouare highlyexperienced
intuningpropellersforspecialized
competitionwork such aspylon-racing.
Take care that the glow plug clip or battery
leads do not come into contactwith the
propeller.Alsocheck the linkage to the
throttle arm. A disconnected linkage could
alsofoul thepropeller.
Afterstarting the engine, carry outany
needle-valve readjustments froma safe
position behind the rotating propeller. Stop
the engine before attempting to make other
adjustments to the carburetor.
5

NOTES
Adjust the throttle linkage so that the engine
stops when the throttle stick and trim lever
on the transmitterare fullyretarded.
Alternatively,the engine maybestopped by
cutting off the fuel supply. Never try to stop
the enginephysically.
Take care that loose clothing(ties,shirt
sleeves, scarves,etc.)do not come into
contact with the propeller.Donotcarry loose
objects (such aspencils, screwdrivers, etc.)
ina shirtpocket from where they could fall
throughthepropellerarc.
Do not start your engine inanarea
containing loose gravel or sand.
The propeller may throw such material in
your face andeyes and cause injury.
For theirsafety,keep all onlookers
(especially small children) wellback (at
least 20 feetor 6 meters) when preparing
your modelforflight. Ifyou have to carry
the model to the take-offpoint with the
engine running, be especially cautious.
Keep the propeller pointed away from you
andwalk well clear of spectators.
Warning! Immediately aftera glowplug-
ignitionengine has been run and isstill
warm, conditions sometimes existwhereby
itisjust possible forthe engine to abruptly
restart ifthe propeller iscasually flipped
over compression WITHOUT the glowplug
battery being reconnected. Remember this
ifyou wish to avoid the risk of a painfully
rapped knuckle!
6

ENGINE CONSTRUCTION
With this engine,the piston will
feel tightatthe top of itsstroke
(TDC) when the engine iscold.
This isnormal.
The cylinder bore Isa little
tapered.
Thepistonand cylinder are
designed to achieve a perfect
running clearance when they
reach theirrunningtemperatures.
When theengineiscold.Whentheengineishot
Crankshaft
Alittletapered
Piston
CylinderLiner

NOTESWHENAPPLYING
ANELECTRICSTARTER
Donot over-prime. This could
cause hydraulic lock and damage
the engine on application of the
electric starter.
Ifover-primed, remove glowplug,
close needle-valve and apply
starter to pumpoutsurplus fuel.
Cover the head with waste to
prevent pumped out fuel coming
intoyoureyes.
8

INTRODUCTION
The FL-70isanair-cooled, overhead-
valve four stroke enginefor modelaircraft
use.This engine issuitable fortrainer,
sportandscale models.
This engine reduces maintenance by
incorporating the firstO.S. ringless
piston/liner assembly.Also, a sealed front
bearing prevents oil leaks. The engine is
fitted with the new easy-to useO.S.60W
airbleed carburetor. This engine is
designed so that more R/0 pilots,from
hobby beginners toskilled Sunday fliers
mayenjoy the performance advantages
of fourstroke engines - greater fuel
economy, higher torque, lower noise and
realisticsund.
STANDARD ACCESSOIES
GlowPlugType F
(fittedwith theengine)
F-4030SilencerAssembly
TNipple
9

Items necessary for starting
GLOW PLUG
O.S.Type F glowplugisinstalledinthe
engine.
GLOWPLUG IGNITER
Commercialy available handy
glowplug heater inwhichthe
glowplug battery and battery
leadsareintegrated.
FUELPUMP
Alternatively,one of the
purpose-mademanual or
electric fuel pumps may be used
to transfer fuel directly from your
fuel containerto the fuel tank.
FUEL
The FL-70 should beoperated on a methanol
based fuelcontainingnot lessthan20%
(volumetric) castor oil, or a top qualitysynthetic
lubricant (ora mixtureof both), plus a small
percentage (5-15%)of nitromethane for improved
flexibility and power. (The carburetorisadjustedat
the factory fora fuel containing 20% lubricant and
15%nitromethane.)Some commercial fuels also
contain coloring additivesas an aid to fuellevel
visibility. Insome cases,these additives have
indicated slightly negative effectso performance.
We would suggest that you use such fuelsonly if
you are satisfiedthat they donot adverselyaffect
running qualities when compared withfamiliar
standard fuels. When changing to a fuel brand or
formula that isdifferentfrom the one
to which you are accustomed, itisa
wise precaution to temporarily revert
to in-flightrunning-in procedures,
untilyou are sure that the engine is
runningentirely satisfactorily.
BEFORE STARTING
Tools, accessories, etc.The following itemsare
necessary foroperating the engine.
10

Reminder!
Model engine fuel ispoisonous. Donot
allow itto come intocontact with theeyesor
mouth.Always store itina clearly marked
container and outofthe reach of children.
Modelenginefuel isalso highlyflammable.
Keepitaway from open flame, excessive
heat,sources of sparks, oranything else
which mightigniteit.Donotsmoke, or allow
anyoneelseto smoke,nearto it.
ElectricStarterand
StarterBattery
Required when starting
theengine.
12-Voltlead-acidbattery
ElectricStarter
O.S.SuperFilter(FuelCan Filter)
Fita filter to the outlet tube of your
refueling container to prevent entry of
foreign matter into fueltank. O.S.
'Super Filters' (large and small)are
availableasoptionalextras.
O.S.Non-BubbleWeight
Toprevent the pickup from adheringto
the tank wall under suction and
restricting fuel flow, slots maybefiled
Ithe end of the weight. Alternatively,
O.S.Non-Bubble Weight isavailable
asan optional extra.
FuelFilter
Itisrecommended to fit a good
in-line filter between the fuel tank
andcarburetor to prevent entry of
foreignmatterintothecarburetor.
FuelTank
Afuel tank of approximately
300cc capacity issuggested.
This allows around 10minutes
flying time, dependent upon the
type offuel used, the size of propeller andon
the proportion of full-throttle to part-throttle
operationthroughouttheflight.
11

Spinner
Sincethe FL-70 isintendedto be
started with an electric starter, the
additionof a spinner assembly for
centering the starter sleeve is desirable. Use a
heavy-duty,well balanced spinner either of
metalorplastic.
SILICONE FUEL LINE
Heatproof silicone tubing of
approx. 5mmo.d.and 2.5mm
i.d.isrequiredforthe
connection betweenthe fuel
tankandengine.
Propellers
Thechoice of propeller depends onthedesign
andweight of the aircraft and o the type of
flying inwhich you willbeengaged. Determine
the best sizeand typeafterpractical
experimentation. Asa starting point, refer to
the props listed inthe accompanying table.
Slightlylarger, oreven slightlysmaller,props
than those shown inthe table maybeused,
but remember that the propeller noise will
increase if blade tip israised, due to higher
rpmor ifa larger-diameter/lower-pitched prop
isused.
Sport& Aerobatic
Trainer& Scale
12X7,12.5X6, 13X6
12.5X6, 13X6-7
Warning:
Make sure that the propeller iswell
balanced.An unbalanced propeller and/or
spinnercan cause serious vibration which
may weaken parts of the airframe oraffect
the safety of the radio-controlled system.
DONOT forget the WARNINGS and NOTES
onpropellerand spinnersafety given on
front pages.
Reminder!
Never touch, orallow any object to come Into
contact with, the rotating propellerand donot
crouch over the engine when itIsrunning.
12

•TOOLS
HEX WRENCH
Necessary forengine installation.
1.5mm,2mm,2.5mm,3mmoppositeside
LONGSOCKET WRENCH WITH PLUG GRIP
Recommendedforeasyremovaland
replacementof the angled and recessed
glowplug,the O.S.LongSocketWrench
incorporates a specialgrip.
PlusThreaded Drivers
No.1,No.2,etc.
8mm
Spanners
8mm, 13mm,14mm,etc.
SCREWDRIVER
Necessary forcarburetor adjustments.
No.1,No.2,etc
Box Wrenches
5.5mm,7mm,8mmoppositeside
13
Nipper

EngineParts Name
RockerCover
14
F-4030SilencerAssembly
ExhaustHeaderPipe
NippleNo.1
(Largerhole)
NippleNo.5
(Smallerhole)LockNut
PropellerWasher
CoverPlate
RotorGuideScrew
ThrottleLever
AirbleedScrew
GlowPlug
LockNutSet
DriveHub
BeamMount
Crankcase
Carburetor
Type 60W
SilencerBody
Needle

INSTALLATION
Because theFL-70 isa powerful,large-displacement,single-cylinderfour-stroke-cycle engine,itis
essential touse very substantial engine mounting. Conventional wooden mountingbeams should be
ofrigidhardwood andof at least15mmor5/8-in square section.
Make sure that the mountingbeams are paralleland that their
topsurfaces are inthe same plane.
Frontview Sideview
Topsurfacesareinthesameplane.Oppositebeam
Topsurfaces are notinthe
sameplane.
Enginedoesnotrestfirmly.
Re-align the surfaces
as necessary
Topsurfacesare not
inthe sameplane.
INCORRECT
CORRECT
15

Howtofastenthemountingscrews.
15mm min
Radialmotor mount
(cast aluminum)
Hardwood such as
cherry or maple.
Steel washer
3mmsteel screw
3mmsteel Allen screw
Spring washer
•Makesure thatthese mountingbeams are
accurately aligned and firmly integrated with
the airframe,reinforcingthe adjacent
structure to absorb vibration. Use 3mm or
larger steelscrews,preferablyAllentype
hexagon sockethead cap screws,with
washers andlocknuts,for boltingthe engine
to the bearers.
INSTALLINGTHEGLOWPLUG
Install washeron glowplug and
insert carefully into cylinder-head,
making sure that itisnotcross-
threaded before tighteningfirmly.
Glow plug
Washer
3mmsteelnuts
Tighten second nut
firmlydown onto first nut.
Tightenthisnutfirst.
Springwasher or
lockwasher
15mmmin.
Hardwood mountingbeams
16

SILENCER & EXHAUST HEADER PIPEINSTALLATION
Screw theheaderpipeintothecylinderhead
untilit"bottoms" , then unscrew sufficiently to
achieve the desired exhaust angle and tighten
the lock nut securely witha 14mm wrench.
Screw the silencer onto the outer end of the
header pipe and tighten the other locknut.
The application of a heatproof silicone sealant
to the threads of the exhaust system is
recommended to reduce the risk of joints
loosening andthe leakage of exhaust gasses
andoilresidue.
Reminder:
Modelengines generate considerable heat
and contact with the header pipeorsilencer
may resultina serious burn.
Ifyou needtotighten the silencer joints,
which may loosen when they are hot,usea
thick folded cloth for protection.
17
LockNut
Exhaust HeaderPipe
Apply siliconesealant.

FUELTANK & LINES
Make sure that the tankiswell rinsed out
with methanol or glow fuel before installation
and that the pickup weightiswell clear of the
bottom of the tank when heldvertically.
Connect between pressure nipple onthe
silencer (larger hole one) and the tank to
apply muffler pressurized fuel feed system
which deliver the fuel stably reducingfuel
level negative effect.
Connect between breather nippleonthe
coverplate and silencer breather nipple
(smaller holeone).
General Piping
Make connectionsas shown inthe Fig.1.
An airbleed type carburetor is required to set
idlingr.p.m. a littlehigherto prevent engine
cutting.
Piping suitable for acrobatic flights
With the general piping,the fuel inthe tank
mayflowinto the silencer when the throttle is
set to slow during upside-down flightor
vertical dive, which may result inengine stop
dueto mixture change at low speed. Piping
shown inthe Fig2 prevents fuel flowing into
the silencer, and engine stop atslow running
during maneuvers. Also, this piping allows to
set the idling r.p.m. a little lower andlonger
flightby preventing excess fuel flowing out.
When thetankisfilled (when thefuel levelis
higher thanthe carburetorcenterline.),
prevent the fuel flowing into the carburetor
with a commercially commercially available
fuel stopper, etc. Release thestopper before
startingthe engine.
18

Fig.1 GeneralPipingNote:When cutting siliconetubing,
useknife orrazorblade.
Plug(commerciallyavailable)
No.5Nipple(smallerhole)
SiliconeTubingDonotusewirecutter
orpliers.
Ifyoushouldneedto cleanoutsilicone
tubes, use methanol orglow fuel, not
gasolineorkerosene.
No.1Nipple(largerhole)
FuelFitter (commercially available)
FuelStopper(commerciallyavailable)
Carburetor
CenterLine
FuelTankCenterLine
Approx. 10mm
Refueling
tubing
TNipple(supplied)
19