Dynamite DYN0891, DYN0890 Owner's Manual

Congratulations on your purchase of a Mach .28 engine!
Precision manufactured and assembled, your Mach .28
will provide you with trouble-free performance if you read
and follow these instructions.

Using the Proper Fuel and Glow Plug

Using the proper fuel and glow plug is critical in order to
achieve maximum performance and reliability. You must
use fuel, glow plugs and air filters that are specifically
designed for model car/truck/buggy applications. Never
use any type of model airplane glow fuel! Use
of model airplane fuel will damage your engine and
immediately void any warranty.

We recommend using Blue Thunder™ or Blue Thunder
Race Formula blend fuels with 20% nitro, providing the
best combination of power and fuel economy. Dynamite®
Blue Thunder fuels are vigorously tested, researched
and formulated to deliver excellent power as well as
engine protection.

A glow plug has been included and is ideal for breaking-in
your new engine. In fact during the break-in procedure, it
is not uncommon to go through one or two glow plugs, as
microscopic bits of metal (from the cylinder/piston wearing
in) bond themselves to the plug element causing glow
plug failure. We recommend the Dynamite MC-59 McCoy
Power Plug (DYN2508) as the absolute best glow plug for
this engine. Delivering an ideal balance of performance
and longevity, this is the same glow plug that continues to
win races at every level of competition, from local events to
World Championships.

All car engines must use a properly oiled air filter to keep
dirt out of the engine. Any dirt that enters the carburetor
can immediately destroy your engine! We recommend
DYN2814 as an excellent choice for a quality air cleaner.

Carburetor Adjustments

Your Mach .28 engine comes equipped with a precision
slide-valve carburetor. Take a moment to review the
pictures below to familiarize yourself with the various
functions of the carb. Loosening the nut located on the
side of the crankcase under the carburetor body will
allow you to rotate the carburetor. Make certain to mount
the throttle arm to the side required by your
particular vehicle.

Although preset at the factory, some changes in the
needle setting can occur during shipping and handling.
We suggest the following settings for breaking-in your
engine:

High-Speed Needle: 31/2 turns out (counterclockwise)
from closed.

Low-Speed Needle: 2 turns out (counterclockwise) from
closed.

When checking the adjustment of the low-speed
needle, it is crucial that the throttle slide is closed
completely when turning the needle and that you
do not over-tighten the needle. Use a Dynamite

®

engine-tuning screwdriver (DYN2775) to make this
job easier. When you feel resistance in the needle,
immediately stop turning and begin turning the
needles counterclockwise, counting the number
of turns from “closed.”

Starting Your Engine for the First Time

The first start of your engine is the most critical time of
the engine’s life, dictating how well it will perform. After
installing the engine in your model and inserting the glow
plug, turn on your radio system and attach a glow igniter
to the glow plug.

When using a recoil starter, never pull the rope out
to its full length, as doing so may cause damage
and recoil starter failure. Quick, short pulls of the
recoil starter are the best technique to use. Never
extend the starter rope more than 12 inches.

Should the pull-starter be extremely difficult to pull (will
not extend out of the assembly), the engine may be
flooded (hydro-locked). Excess fuel between the cylinder
head and piston will not allow the piston to travel through
its full range of compression, effectively “locking up” the
engine. Should this occur, immediately remove the glow
igniter from the plug. Using a quality glow plug wrench
(DYN2510), remove the glow plug and turn the model
upside down. Give the recoil starter a few short pulls to
clear out the fuel, re-install the glow plug and start again.

We recommend using an electric starter or starter box for
the initial starts, even with a pull-start equipped engine.

You may need to “blip” the throttle on the transmitter
(applying throttle on/off) while trying to start the engine,
as new engines are more difficult to start due to the tight
piston/cylinder fit. Never start an engine above

1

⁄4 throttle! Immediate damage to your engine can

and will occur!

When the engine starts, the exhaust should emit
lots of blue/white smoke, indicating that the engine is
excessively rich (a good thing during break-in). During
the first tank of fuel, you may wish to set a higher than
normal idle speed and/or leave the glow plug igniter
attached in order to keep the engine from stalling. Drive
your vehicle around while “blipping” the throttle and avoid
operating the engine at full throttle for more than
2–3 seconds at a time. Consume the entire first two
tanks of fuel in this manner.

After the first two tanks of fuel, begin leaning out the
high-speed needle valve 1/8 turn at a time. It generally
takes about 5 or 6 tanks of fuel before you’d want to
start tuning for “maximum” power. Do not skip this

process of breaking in a new or rebuilt engine!
Should you choose not to follow these procedures,
you risk damaging your engine during the first
tank of fuel.

Your patience during these procedures will be rewarded
by an engine that performs reliably and to its maximum

power potential. First run attempts can be more frustrat­ing than with other (less powerful) sport engines, so take
your time—it will be worth the wait!

Glow plug failure is a common occurrence when break­ing in a new engine. To test your plug, let the engine idle
at a properly adjusted low-speed needle setting with the
glow igniter attached. Then, remove the igniter. If you
hear no appreciable change in engine rpm, then the
plug is still good. If the engine loads up and the rpm’s
decrease, it’s time to replace the glow plug.

Setting the Needle Valves

When tuning the needle valves for maximum
performance, adjust them is small increments, 1⁄8 turn
at a time.

An engine should not be run too lean; doing so severely
shortens the life of the engine. When an engine is set too
lean, it will run very strong at first but will soon begin to
sag and hesitate or stall when accelerating.

The best way to tune an engine is by using an infrared
temperature gauge, but you can also use water to check
the head temperature. (Refer to “Tuning the High-Speed
Needle” below.)

Tuning the High-Speed Needle

To obtain the correct high-speed needle setting, start
the engine and drive your vehicle around for a minute
or two, applying full throttle for periods of 5 seconds or
more. Place a drop of water on the cylinder head. If the
water sizzles away (evaporates immediately) the needle
setting is too lean. A correct needle setting will result in
the water evaporating after 3–5 seconds. If the water
does not evaporate, chances are good that the needle
setting is too rich. Lean the needle 1/8 of a turn and
run the engine again, adjusting the needle setting to get
the desired evaporation time. Check the temperature

each time you change the needle mixture. Do not
let the engine overheat, as this will damage the
engine!

Tuning the Low-Speed Needle

The low-speed needle (also referred to as the idle mix­ture or idle needle) should be set after you’re satisfied
with the high-speed needle setting. After achieving the
proper operating temperature, reduce the engine throttle
to idle and pinch the fuel line for 3–5 seconds with your
fingers close to the carb fuel inlet nipple. If the engine
dies immediately, the low-speed needle is set too lean.
If the rpm’s increase dramatically, the setting is too rich.
The ideal setting results in the rpm’s increasing just
a slight amount after pinching the fuel line.

Mach .28

Owner’s Manual

Leaner

Low-Speed
Needle Valve

High-Speed Needle Valve

Idle Stop Adjustment

Faster Idle
(clockwise)

Slower Idle
(counterclockwise)

Leaner

Fuel Inlet
(Adjustable)

8002_DYN_mach28_manual.indd 1 5/31/05 9:00:23 AM

Idle Stop Adjustment

The last setting to be made is the idle stop screw.
Turning this screw clockwise increases the idle speed;
whereas turning the screw counterclockwise will make
the engine idle at a lower speed. Ideally, the engine
should idle just fast enough to be reliable in acceleration
and transition from idle to full speed. Avoid an idle speed
that is too fast, as it will cause damage to your clutch.

Engine Maintenance

Periodic maintenance must be performed in order
to keep your engine in proper operating condition. After
each day of running, it’s critical to use high quality after­run oil to protect the internals of the engine and protect
them against corrosion. The methanol used in the fuel
attracts moisture that can cause corrosion (particularly in
the ball bearings). We recommend Blue Thunder™ Final
Run (DYN2255) as it’s specifically formulated to protect
your engine between uses. Follow these steps after
running your engine:

1) Empty all fuel from the tank and fuel lines

2) Use Final Run fuel following the instructions on
the container

3) Clean and inspect the engine, air cleaner and
fuel system

Troubleshooting Guide

Problem

Engine won’t start

Engine starts, then dies

Engine starts and runs
for 1⁄2 tank, then quits

Spare Part Listing

Stock # Description
DYN0900 CYLINDER HEAD SCREW (4): Mach .26/.28
DYN0945 CYLINDER HEAD: MACH.28
DYN0946 HEAD BUTTON: MACH.28
DYN0947 HEAD GASKET .1mm: MACH.28
DYN0948 HEAD GASKET .2mm: MACH.28
DYN0949 PISTON/SLEEVE: MACH.28
DYN0950 WRIST PIN: MACH.28
DYN0907 WRIST PIN CLIPS: MACH.26/.28
DYN0908 CONNECTING ROD: MACH.26/.28
DYN0951 SLIDE VALVE CARB: MACH.28
DYN0910 O-RING SET: MACH.26/.28
DYN0952 CARB RET. POST SET: MACH.28
DYN0912 COLLET: MACH.26/.28
DYN0913 FRONT BEARING: MACH.26/.28
DYN0953 CRANKCASE: MACH.28
DYN0915 REAR BEARING: MACH.26/.28
DYN0954 CRANKSHAFT (w/ PS) SG: MACH .28
DYN0955 CRANKSHAFT (w/o PS) SG: MACH .28
DYN0922 BACKPLATE (w/o PS): MACH.26/.28
DYN0923 THROTTLE BARREL: MACH.26/.28
DYN0956 THROTTLE BARREL BOOT: MACH.28
DYN0925 BALL END: MACH.26/.28
DYN0926 CARB. BALL LINK: MACH.26/.28
DYN0927 LOW-SPEED NEEDLE: MACH .26/.28
DYN0928 IDLE SCREW: MACH.26/.28
DYN0929 HIGH-SPEED NEEDLE: MACH.26/.28
DYN0930 HIGH-SPEED NEEDLE HOLDER: MACH.26/.28
DYN0931 HIGH-SPEED NEEDLE WASHER: MACH.26/.28
DYN0932 FUEL INLET NIPPLE: MACH.26/.28
DYN0957 CARB BODY: MACH.28
DYN0958 THROTTLE SPRING: MACH.28
DYN0934 PS COMPLETE: MACH.26/.28
DYN0935 PS HANDLE & EXT.: MACH.26/.28
DYN0936 PS BACKPLATE: MACH.26/.28
DYN0937 PS SCREW SET: MACH.26/.28
DYN0938 PS RECOIL SPRING: MACH.26/.28
DYN0939 PS ROPE/PULLY: MACH.26/.28
DYN0940 PS FRONT SET: MACH.26/.28
DYN0941 PS ONE-WAY BEARING: MACH.26/.28
DYN0942 PS BACKPLATE: MACH.26/.28
DYN0943 PS SHAFT: MACH.26/.28

Warranty

Mach .28 engines are guaranteed against original
defects in materials and workmanship for a period of 90
days from date of purchase. Mach .28 engines are of
excellent quality and designed to provide many hours of
racing enjoyment. If cared for properly, these engines are
extremely durable. However, normal “common sense”
care must be given to your engine in order to maximize
its performance and service life. The following conditions/
problems cannot be covered under warranty:

• Recoil starter

•Damage due to lack of maintenance

• Rusted bearings

• Crash-related damage (over-revving, runaways,
free-wheeling, etc.)

• Damage due to use of improper fuel or glow plugs

• Damage due to lean runs (seized connecting rods,
pistons, etc.)

• Damage caused by dirt or foreign objects being
ingested into the engine

• Damaged from improper disassembly or reassembly

• Modification of any kind

• Normal engine wear

Should you need to send your engine in for warranty or
non-warranty repairs, please follow these steps:

1) Ship your engine (in its original box) packed inside

a sturdy box, freight prepaid to:

Horizon Service Center
ATTN: Mach .28 Service
4105 Fieldstone Rd.
Champaign, IL 61822

2) Include a note containing a brief summary of

the problems you are experiencing with your
Mach .28 engine. Please tell us:

• Nitro content and brand of fuel used in

the engine

• Type of glow plug used

• Type of air cleaner used

• Approximate running time on the engine

prior to difficulties developing

Date your correspondence and include your return

shipping address, as well as a daytime telephone
number and e-mail address (if applicable).

3) Warranty Repair
If you believe that the problem(s) with your
engine are covered under warranty, you must
include your original dated sales receipt to verify
proof of purchase date. Providing the conditions
of warranty have been met, your engine will be
repaired without charge.

4) Non-Warranty Service
Should your repair costs exceed $50.00, you’ll
be provided with an estimate advising you of your
options. Any charges for return shipping of non­warranty repairs will be billed to you.

5) Payment Method
Please advise the Horizon Service Center
of the method of payment you prefer to use.
The Service Center accepts Visa or MasterCard.
When using credit cards, please include your
card number, expiration date and the name
as it appears on the card

Possible Cause/Solution

• Reset needles to the
factory setting

• Incorrect needle settings

• Out of fuel/old, bad or
improper fuel

• Clogged fuel line

• Bad or improper glow plug

• Glow igniter not charged

• Engine flooded

• Pressure line blocked or
disconnected

• Bad glow plug

• High-speed needle too lean

• Hole or tear in fuel line

• Bad glow plug, idle speed
set too low

• Overheated engine
(too lean)

• Improper needle settings

For additional information or your nearest
Dynamite dealer, go directly to the Dynamite
Web Site at www.DynamiteRC.com or call
toll-free 877-504-0233.

Mach .28 engines are manufactured in Taiwan and
distributed worldwide by:

Horizon Hobby, Inc.

4105 Fieldstone Rd.

Champaign, IL 61822

www.horizonhobby.com

8002

© 2005 Horizon Hobby, Inc.

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