Losi LOSR1001 User Manual

Owner’s Manual

Congratulations on your purchase of a Losi Sport Mach
26SS engine. Precision manufactured and assembled,
your engine 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 can damage your engine and
immediately void any warranty.

We recommend using Team Losi® Nitrotane™ fuel with
20% nitro, providing the best combination of power
and fuel economy. Team Losi 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 glow
plug (DYN2508) as the absolute best glow plug for this
engine. This glow plug has been designed to deliver an
ideal balance of performance and longevity.

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 LOSB5020 as an excellent choice for a
quality air cleaner.

Carburetor Adjustments

Your engine comes equipped with a precision slide­valve 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.

High-Speed
Needle Valve

Low-Speed
Needle Valve

Fuel Inlet
(Adjustable)

Leaner

We suggest the following settings for breaking in
your engine:

Faster Idle
(clockwise)

Leaner

High-Speed Needle: 3 turns out (counterclockwise)

Low-Speed Needle: 2

Slower Idle
(counterclockwise)

Idle Stop
Adjustment

from closed.

1

/4 turns out (counterclockwise)

from closed.

When checking the adjustment of the low­speed 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 an engine-tuning screwdriver such
as SWK9912 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 good quality glow plug wrench,
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.

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
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, 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 in small increments,
1⁄16 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”).

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 frequently. 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 1/16 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 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.

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). Follow these steps after running
your engine:

1) Empty all fuel from the tank and fuel lines

2) Remove the glow plug and air filter and add
5 to 6 drops of a quality after run oil into the
carburetor and cylinder head openings. Turn
the engine over a few times to distribute the oil
throughout the engine.

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

Possible Cause/Solution

• 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

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.