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Engine Bolts and Firewall Requirements

The engine should be mounted to either a glass-filled nylon engine mount, 

a  machined  aluminum  engine  mount,  or  an  integrated  hardwood  beam 

mount.  Use  only  high-quality  6-32  or  4mm  steel  socket-cap  screws  and 
related hardware to mount the engine to the engine mount. The firewall in the 

aircraft should be aircraft grade 5-ply plywood no less than 1/4" thick and the 

firewall should be reinforced to meet the torque and weight of the engine.

Fuel Tank Size and Orientation to Carburetor

Ideally, the stopper in the fuel tank should be level with the high speed needle 
valve or just slightly below it. Some models will only allow the fuel tank to be 
mounted higher than the ideal location. A fuel tank that is positioned higher 
than the ideal location usually doesn’t pose any problem except when it is 
mounted excessively higher and/or is used in conjunction with an inverted 

mounted engine or during extreme aerobatic flight. If you mount the  engine 

inverted, we strongly suggest lowering the fuel tank so the stopper assembly 
is slightly below the high speed needle valve. Doing this will prevent fuel 

from siphoning into the engine and flooding it. If you cannot lower the fuel 

tank far enough, we suggest lowering it as far as can be allowed in your 
particular application.

The size of the fuel tank used should be 10oz.~12oz., depending on the 

model and the length of flights desired. Use of a 12oz. tank will provide 

approximately 15 minutes of run time at full throttle. Use of a fuel tank any 

larger than 12oz. can lead to excessive leaning of the engine during flight 

and is not recommended.

Carburetor Installation

The carburetor is held in place using two socket-cap screws provided. Slide 

the base of the carburetor into the 
crankcase, being careful to keep 
the  carburetor  perpendicular  to 
the  front  of  the  engine.  Using 

your thumb, push down firmly on 

the carburetor so that the base of 
the  carburetor  sets  completely 
into the crankcase. An o-ring is 
installed on the carburetor throat 
to seal the joint. While holding the 

carburetor firmly down into place, install and 

GENTLY

 tighten the socket-cap 

screws using the hex wrench provided.

WARNING

  Do not overtighten the socket-cap screws or you might strip 

the threads in the carburetor, resulting in replacement of the carburetor.

Muffler Installation

The muffler is mounted to the engine using the two socket-cap screws, two 

split washers and one of the two 
gaskets  provided.  The  second 
gasket should be kept as a spare. 
Tighten  both  screws  firmly  to 

prevent the muffler from loosening 
during  flight. The  exhaust  cone 
on  the  back  of  the  muffler  can 

be adjusted to better match the 
installation  of  your  particular 
application. To adjust the exhaust 

cone, loosen the retaining nut, rotate the cone to the desired angle, then 

tighten the retaining nut firmly while holding the axial bolt in place from the 
front of the muffler. 

It is important to tighten the retaining nut firmly to 

prevent the exhaust cone from loosening during flight.

Carburetor Idle Stop Screw and Adjusting the Idle Speed

The  idle  stop  screw  holds  the  throttle  barrel  in  the  carburetor  body  and 

also  adjusts  the  closure  of  the 
throttle  barrel.  We  recommend 
adjusting the idle stop screw to 
allow the throttle barrel to close 
completely.  This  will  allow  you 
to adjust the idle speed via your 
transmitter;  therefore,  you  will 

need to set up your transmitter throttle trim lever to keep the engine at a low 
idle when the trim lever is centered, then to shut off the engine when the trim 
lever is pulled all the way back. To adjust the idle stop screw

, first loosen the 

hex nut using an adjustable wrench, then loosen the idle stop screw (turn 
counter-clockwise) to allow throttle barrel to close more, or tighten the idle 
stop screw (turn clockwise) to make the throttle barrel stay open more. 

When satisfied with the adjustment, tighten the hex nut firmly.

Needle Valve Extension

If an extension is required to adjust the high speed needle valve, use a 

1.5mm diameter wire of the necessary length (not included). Loosen the 
grub screw in the side of the needle valve using a 1.5mm hex wrench, insert 

the wire into the end of the needle valve, then tighten the grub screw firmly.

Throttle Arm Position

The  throttle  arm  angle  can  be  adjusted  to  better  suit  your  particular 
application. Using a 1.5 hex wrench, loosen grub screw in the side of the 
throttle arm, then adjust the angle of the throttle arm either forward or 

backward, and firmly tighten the grub screw.

Propeller Installation

WARNING

  

Before installing the propeller it must be balanced. Running 

your engine using an out-of-balance propeller can lead to excessive vibration, 
which will result in excessive stress and wear on both the engine and the 
airframe. Balance the propeller using the method recommended by the 
propeller manufacturer. Several products are available to properly balance 
propellers. Ask your local retailer for more information about these items.

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Global Services 

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18480 Bandilier Circle 

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Fountain Valley, CA 92708 

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Phone: (714) 963-0329 

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Fax: (714) 964-6236 

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Email: [email protected]

Rear Needle Valve Assembly Installation - Optional

Your XLS Series engine comes with the needle valve preinstalled in the 

carburetor. Also included is a rear needle valve assembly which can be 
installed in place of the carburetor mounted needle valve assembly. By using 
the rear needle valve assembly, adjusting the needle valve is safer because 
it's further behind the spinning propeller.

To mount the rear needle valve 
assembly,  use  an  adjustable 
wrench to unscrew and remove 
the needle valve assembly from 
the  carburetor  and  to  unscrew 
and  remove  the  plug  from  the 
rear needle valve mount.

Carefully thread the needle valve assembly into the rear needle valve mount 

and tighten it firmly, then carefully thread the plug into the carburetor and 
tighten it firmly. Remove the two upper backplate mounting screws, then 

install and tighten the two longer socket-cap screws and split washers 
(included with the rear needle valve assembly) to secure the rear needle 
valve assembly to the engine backplate. Connect the length of fuel tubing 
provided between the chrome fuel nipples on the rear needle valve assembly 
and the carburetor. The fuel pick-up line from your fuel tank should be 
connected to the larger brass nipple on the rear needle valve assembly.

Summary of Contents for XLS .52A

Page 1: ...tments to the needle valves Do not reach over or around the propeller Do not lean toward the engine Do not wear loose clothing or allow anything to be drawn into the spinning propeller while the engine is running l If you need to carry your model while the engine is running be conscious of the spinning propeller Keep the aircraft pointed away from you and others at all times l Do not use a tight f...

Page 2: ...The idle stop screw holds the throttle barrel in the carburetor body and also adjusts the closure of the throttle barrel We recommend adjusting the idle stop screw to allow the throttle barrel to close completely This will allow you to adjust the idle speed via your transmitter therefore you will need to set up your transmitter throttle trim lever to keep the engine at a low idle when the trim lev...

Page 3: ...sing an electric starter it is not necessary to prime the engine The starter turns the engine over fast enough that the engine draws fuel on its own Priming the engine prior to using an electric starter can cause the engine to hydro lock flood Turning the engine over with an electric starter while the engine is flooded can cause extreme damage to the engine and or cause the propeller assembly to c...

Page 4: ...tachometer this should be between a 200 300 rpm drop q 3 With the engine running at full power carefully lift the nose of the aircraft about 45º into the air The mixture should not become too lean but you may hear a slight increase in rpm If the engine sags or loses rpm when you hold the nose up the mixture is too lean If this is the case slightly richen the mixture and follow the test once more I...

Page 5: ...e you will find helpful This Quick Start Guide should not be used as a replacement for the Operating Instructions included rather it should be used along with the Operating Instructions We highly recommend reading through the Operating Instructions to familiarize yourself with each part of the engine along with the proper procedures for engine break in and tuning Engine Preparation q 1 Mount the e...

Page 6: ...olts 4 Engine does not transition A Failed and or wrong type glow plug A Replace with new recommended glow plug B Old and or wrong type fuel B Replace with new recommended fuel C High speed needle valve set too rich C Set high speed needle valve to leaner setting D Low speed needle valve set too lean D Set low speed needle valve richer E Low speed needle valve set too rich E Set low speed needle v...

Page 7: ...buretor Base O Ring 282412 40845 Low Speed Needle Valve O Ring 282452 46845F High Speed Needle Valve O Ring 282501 91137 Fiber Washer 282608 46837F Idle Stop Screw with Nut 283022 S40801F Carburetor Assembly Complete 283023 S40803F Carburetor and Rear Needle Valve Assemblies 284206 12830 High Speed Needle Valve Seat 284220 S52103X Cylinder Head 284221 S52112 Cylinder Head Gaskets 2 284222 S52203 P...

Page 8: ...DIMENSIONS A 3 3 8 B 3 1 2 C 4 3 4 D 2 7 8 E 3 1 2 F 11 16 G 1 1 8 H 1 7 16 I 1 3 4 J 2 1 16 K 1 1 16 L 1 7 16 M 1 3 4 N 7 16 Use this drawing to help you determine engine mounting requirements Drawing is not to scale and is generic in nature XLS ...

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