High Speed, Mid Range And Low Speed Needle Valves; Resetting The Needle Valves To The Factory Settings; Starting Procedure; Break-In Procedure - SH Engines SH .21 XB Operating Instructions Manual

HIGH SPEED, MID RANGE AND LOW SPEED NEEDLE VALVES

High speed Needle Valve
The.high.speed.needle.valve.is.preset.from.the.factory.for.the.initial.starting.
procedure..do not make adjustments to it at
this time..The.high.speed.needle.valve.is.used.
Turn.Clockwise
to.Lean
to.meter.the.air/fuel.mixture.at.full.throttle..Turn.
the.needle.valve.clockwise.to.lean.the.mixture.or.
Turn
Counterclockwise
to.Richen
turn.the.needle.valve.counterclockwise. to. richen.
the.mixture.
Check to ensure that the high speed needle valve is set at 3 full turns
out from the closed position for the break-in process.
Mid Range Needle Valve
The.mid.range.needle.valve.is.preset.from.the.factory.for.the.initial.starting.procedure.
and normal use, and is used fine-tune the air/fuel
mid. range. mixture.. Turn. the. needle. valve.
clockwise.to.lean.the.mixture.or.turn.the.needle.
Turn.Clockwise
to.Lean
valve.counterclockwise.to.richen.the.mixture..do
not make adjustments to the mid range need
Turn
Counterclockwise
valve until after tuning both the high and low
to.Richen
speed needle valves, and until afTER the engine has been broken in.
low speed Needle Valve
The.low.speed.needle.valve.is.preset.from.the.factory.for.the.initial.starting.
procedure..do not make adjustments to it at
this time..The.low.speed.needle.valve.meters.
the.air/fuel.mixture.at.idle.and.during.transition.
Turn.Clockwise
to.Lean
from. idle. to. full. throttle..Turn. the. needle. valve.
clockwise.to.lean.the.mixture.or.turn.the.needle.
Turn
Counterclockwise
to.Richen
valve.counterclockwise.to.richen.the.mixture..The.
low.speed.needle.valve.is.preset.from.the.factory,.but.minor.adjustments.may.
need.to.be.made.to.suit.your.application:.fuel.used,.glow.plug.and.environment.
all.contribute.to.the.setting.
do not adjust the low speed needle valve until afTER the engine has
been broken in.

RESETTING THE NEEDLE VALVES TO THE FACTORY SETTINGS

There.may.come.a.time.when.you.get.the.needle.valve.settings.out.of.spec,.
resulting.in.poor.engine.performance.or.not.even.being.able.to.start.the.engine.
at.all..If.this.occurs,.reset.the.high.speed,.mid.range.and.low.speed.needle.
valves.to.their.factory.settings.as.described.below:
Resetting the High speed Needle Valve
Gently.turn.the.high.speed.needle.valve.clockwise.until.it.bottoms.out.(fully.
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closed)..do not force it or you may damage the carburettor.
Turn.the.high.speed.needle.valve.counterclockwise.(open).3 full turns.
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Resetting the Mid Range Needle Valve
The mid range needle valve should be flush with the carburettor housing.
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Resetting the low speed Needle Valve
Open.the.carburettor.barrel.completely.
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While holding the carburettor barrel open with your fingers, use a flat blade
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screwdriver. to. gently. turn. the. low. speed. needle. valve. clockwise. until. it.
bottoms. out. (fully. closed).. do not force it or you may damage the
carburettor..From.this.point,.turn.the.low.speed.needle.valve.counterclockwise.
3 full turns..

STARTING PROCEDURE

IMPORTANT..We.recommend.using.a.1/8th.scale.starting.box.to.start.
your.engine..We.strongly.suggest.reading.the.operating.instructions.that.
are.included.with.your.starter.box.before.attempting.to.start.the.engine..This.
will.ensure.that.you.are.familiar.with.how.to.use.your.starter.box.properly,.
so.you.don't.damage.your.starter.box.or.your.engine.
q. If. your. vehicle's. fuel. tank. has. a. primer. pump,. press. this. pump. several.
times.to.draw.fuel.to.the.carburettor..When.the.fuel.reaches.the.carburettor,.
stop.priming..Over-priming.the.engine.can.cause.the.engine.to."hydro-lock".
Never try to start the engine if it is hydro-locked. This could cause serious
damage to the engine.
q. If.your.fuel.tank.does.not.have.a.primer.pump,.fuel.will.be.drawn.into.the.
carburettor.when.you.turn.the.engine's.crankshaft.using.your.starter.box.
q. The.engine.is.started.by.connecting.the.power.to.the.glow.plug.then.turning.
the.crankshaft,.using.your.starter.box,.until.the.engine.starts..Once.the.engine.
has.started,.your.vehicle.can.be.removed.from.the.starter.box.
PRO TIP When the engine is new, it can sometimes be difficult to turn
over.and.may.cause.your.starter.box.to.slip..A.trick.to.help.this.is.to.loosen.
the.glow.plug.slightly,.start.the.engine,.then.remove.the.glow.starter.and.
retighten.the.glow.plug..This.effectively.lessens.the.engine's.compression,.
making.it.easier.to.turn.over.the.engine.

BREAK-IN PROCEDURE

The.SH..21.XB.PRO.Competition.Off-Road.engine.features.a.ceramic.piston.
(XB-1.features.an.aluminium.piston).and.a.chrome-plated.brass.sleeve.(liner)..The.
cylinder.sleeve.(liner).is.tapered.at.the.top,.causing.resistance.when.the.piston.
moves.through.the.top.of.the.stroke..This.is.normal..When.the.engine.heats.up.to.
operating.temperature,.this.resistance.will.decrease.and.the.proper.clearance.will.
be.achieved..The.break-in.procedure.will.guide.you.through.the.steps.necessary.
to.properly.break.in.your.new.engine..Please.follow.the.steps.closely.
Breaking in an engine with a ceramic piston is the same as breaking in a standard
aBC engine, except that the break-in period may take a little longer.
do NoT oMiT THE ENgiNE BREaK-iN PRoCEduRE!
The break-in process allows the engine parts to perfectly fit to each other
and.properly.protect.each.part.from.premature.wear..The engine should
be broken in using a good quality R/C car fuel that contains no more
than 20% nitromethane and 10%~14% oil content.
To. make. sure. that. you're. not. leaning. out. the. engine. too.
much. and. overheating. it. during. break-in. and. under. normal.
use,. we. suggest. using. a. temp. gun. to. monitor. the. engine's.
temperature.
during break-in, engine temperature should not exceed
280ºf (138ºC). The optimum engine operating temperature
is 230º~260ºf (110º~127ºC). The minimum engine operating
temperature is 180ºf (82ºC).
q. Follow.the.Starting.Procedure.to.start.the.engine.
q. Once.the.engine.starts,.keep.the.glow.starter.attached.to.the.glow.plug.
and.let.the.engine.run.for.about.10.seconds.without.giving.it.throttle..This.
will.allow.the.engine.to.warm.up..At.this.point.the.engine.should.be.running.
very."rich".and.the.engine.will.also.sound.like.it's.running.rough.
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