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 after-
run 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 non-
warranty 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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