Duratrax VELOCITY 17 User Manual

Thank you for purchasing a DuraTrax engine – designed to provide
easy starts and all the power you'll need for thrilling R/C action.

The following instructions contain information you'll need to break-in,
operate and maintain your new engine like a pro. Read and follow
them carefully, and your engine will provide a long life of strong,
dependable performance.

• Model engine fuel is poisonous and must be kept in a clearly marked
container, stored aw a y from the reach of children.Avoid getting fuel into
your eyes or mouth.

• Because model engine fuel is highly flammable, it should also be kept
away from an ything that might cause it to ignite (including open flames,
excessive heat, or any objects and materials which could produce a
spark). Smoking must not be permitted near the fuel.

• R/C model engine exhaust, like that of automobile engines, contains
deadly carbon monoxide. Do not run the engine in enclosed spaces –
operate it only in open, well-ventilated areas.

• Your engine will become very hot as it runs. Touching any par t – particu­larly the muffler (silencer), cylinder head or exhaust header pipe – could
result in a serious burn. Avoid contact with the engine until it has cooled.

• Protect onlookers – especially small children – by making sure that
they remain at least 60 feet (20 meters) aw a y while y ou start the engine.

• This engine was designed only to power R/C model vehicles and
should not be used for any other purpose.

• Never pull the starter cord out more than 10 inches (25cm).To rewind
the cord, continue holding the handle and let the recoil action pull it
smoothly back into the starter unit. Do not abruptly release the handle.

The High-Speed Needle

The “high-speed” needle is sticking up from the side of the carb. It is
located in the brass housing, just above the fuel inlet. It controls the
fuel-to-air mixture of the carb. The needle is pre-set for break-in from

CARBURETOR SETTINGS

ADDITIONAL PRECAUTIONS

FOR Y OUR SAFETY

INTRODUCTION

ENGINE INSTR

ENGINE INSTR

UCTIONS

UCTIONS

Warranty

• DuraTrax®will warranty this engine for 90 days after the pur-
chase date from defects in materials or

workmanship.DuraTrax
will either repair or replace, at no charge, the incorrectly made
part.

• Make sure you save the receipt or invoice you were given
when you bought your engine! It is your proof of purchase and
we must see it before we can honor the warranty.

• To return your Velocity 17 for repairs covered under warranty
you should send your engine to:

Hobby Services

1610 Interstate Drive

Champaign, Illinois 61822

Attn: Service Department

Phone: [phone]:00 am - 5:00 pm Central Time M-F

E-mail:

[e-mail]

Repair service is available anytime.

• After the 90 day warranty, you can still have your Velocity 17
repaired for a small charge by the experts at DuraTrax’s
authorized repair facility, Hobby Services, listed above.

T o speed up the repair process,please follow these instructions:

Send written instructions which include: a list of all items returned,
a THOROUGH explanation of the problem, the service needed
and your phone number during the day. If you expect the repair to
be covered under warranty, be sure to include a proof of date of
purchase (your store receipt or purchase invoice).Also be sure to
include your full return address.

TM

®

the factory at 2-3/4 turns out from the fully closed position of the carb.
Once the engine is broken-in, the high-speed needle would typically
run from 2-1/4 to 2-1/2 turns out from closed, depending on the weath­er, humidity and altitude above sea level. To richen turn the needle
counterclockwise, to lean turn the needle clockwise.

The Low-Speed Needle

The “low-speed” needle is the screw in the carb body, opposite the throt­tle arm (see picture on previous page).It controls the fuel to air mixture at
low throttle settings.There is a simple wa y of adjusting the low-speed nee­dle correctly called the “pinch test.” With the engine at idle, pinch the fuel
line and listen to how the engine speeds up or slows down.If the engine
increases its speed for about 2 or 3 seconds and then loses RPM, the
needle is set correctly. If the engine loses RPM quickly, it is set too lean
and the low-speed needle needs to be opened (counterclockwise) to
richen the mixture. Pinch again

to check the mixture. If the engine takes

longer than 4

seconds to slow down, lean (clockwise)the low-speed nee­dle and then pinch again to check the mixture. Use small adjustments
when setting the low speed needle.Start with 1/16 turn increments.

The Throttle Stop Screw

On the front of the carburetor, there is a black screw (see picture on previ­ous page).This is called the throttle stop screw.This increases or decreas­es the idle RPM without changing the fuel-to air-mixture.You should see an
opening of approximately 1.5mm (between 1/32" and 1/16") between the
carb body and the carb barrel when the throttle is pushed closed.

Before running, please, read this manual thoroughly to familiarize your­self with this engine.

There are several simple steps to starting the engine:

1. Install a glow plug if one is not in your engine.This threads into the

top of the cylinder head.

2. Fill the tank almost to the top.Leave a little air at the top of the tank.

3. Prime the engine by turning the flywheel on the engine. Watch the

fuel go through the line and when it gets to the carburetor, turn the
flywheel one more full revolution.

4. Open the high speed needle valve exactly 2-3/4 turns out (coun-

terclockwise) from fully closed. Be careful not to overtighten the
high speed needle. When you feel some resistance, stop turning
the needle. The high-speed needle is sticking up from the car-
buretor inside the brass housing. All of the carburetor settings
are adjusted with a flat bladed screwdriver. If you have previously
run the vehicle, keep the same needle valve setting that you used
on your last run.

5. Install your glow plug starter onto the glow plug.

6. Start the engine by pulling the recoil - Use short, quick pulls. DO

NOT pull the recoil starter’s string to the end.You only need 10 inch-
es of pull to start the engine.

If the engine does not start after several pulls, sometimes it is helpful to
start the engine at around half throttle. Have a friend pull back on the
throttle some while you start the engine. This

may

be an indicator that
the low speed needle setting needs to be adjusted. When the engine
starts, immediately return the throttle to idle. If this is not done the
engine can over-rev and cause engine damage. If the engine is diffi-

cult to turn over with the recoil starter,especially if it is brand new,
loosen the glow plug a half turn before starting the engine. This
allows some compression to escape, but the engine will still start.

Make sure you tighten the glow plug after the engine starts.

If the
recoil starter is still difficult to pull, the engine is flooded – there is too
much fuel inside the engine. Remove the glow plug and air cleaner,
then turn the engine upside down and pull the recoil 5 or 6 times.This
will clear the engine of fuel, and you will notice the recoil pulls easier.
Replace the glow plug and repeat the starting procedure.

Fuels

Use fuels that are specially formulated for car and truck engines.
DuraTrax Red Aler t fuel is specially formulated for R/C engines like the
Velocity .17.

How T o Stop Y our Engine

You may have been wondering how to stop the engine.All you have to
do is pinch the fuel line that runs to the carburetor and from the bottom
of the fuel tank. Pinching this will restrict the fuel flow and the engine
will quit within a few seconds. You can also touch the flywheel with the
tip of your shoe through the hole in the bottom of the chassis.

To insure long life and good performance from your Velocity .17 engine,
you MUST break-in the engine. The break-in period is critical for long
life of the internal parts of the engine.This should be done over the first
5 or 6 tanks of fuel.

Some Things To Remember During Break-In:

1. Run with the body off. This will keep the engine cooler.

2. Keep the air cleaner on at ALL times.

3. Run on a smooth, hard surface. An empty parking lot is perfect.

4. Use the same fuel that you will use for normal running.

5. Resist the urge to accelerate and decelerate the vehicle quickly.

6. Break-in puts stress on the glow plug and you can burn it out dur-

ing break-in. Make sure you have an extra plug or two on hand.

7. Do NOT overheat the engine.You can check the head temperature

by using one of the temperature gauges that are available.

The First Tank

Your first tank of fuel should be running the engine at a very r ich high­speed needle valve setting.This allows the fuel to carry as much oil as
possible into the engine to lubricate the internal parts during the break-in.

1. Open the needle valve 2-3/4 turns from fully closed (counterclockwise).

This is factory set already, but check it to make sure.When closing the
high-speed needle, close the needle until you feel some resistance .DO
NOT overtighten or you will damage the engine.

2. Start the engine.

3. Once the engine is started, open the high-speed needle valve

around 1/8 turn at a time, finding the setting where the engine just
barely runs. This may take a few times adjusting the needle, run­ning the vehicle away from you and back, then adjusting the nee­dle.The engine will perform sluggishly and stall from time to time ­that is normal.

4. Run the vehicle back and forth at medium speeds, slowly acceler-

ating and decelerating the vehicle, until the tank is almost out of
fuel. Do not allow the tank to run out of fuel. This leans out the
engine and can cause overheating.

5. Stop the engine and allow the engine to cool before the second

tank. This normally takes around 10 minutes (See How To Stop

Your Engine).

Tanks 2-6

Turn in the needle v alve (clockwise) around 1/12 turn from the previous
setting. Run the vehicle back and forth. You should notice that the
engine will perform better during each run. Stop the vehicle periodical­ly to check for overheating. If it is too hot, stop the engine.Wait for it to
cool, then open up the needle valve 1/4 turn and restart. After the 6th
tank, you should be near to the peak performance of the engine.

BREAKING-IN THE ENGINE

RUNNING THE ENGINE

THROTTLE STOP SCREW

1/32" T O 1/16" GAP