Losi LOSR2800 - Manual

Nitrotec ™ R21 3.5cc Racing Engine
Safety Precautions
This is a sophisticated hobby Product and not a toy. It must be operated with caution and common sense and
requires some basic mechanical ability. Failure to operate this Product in a safe and responsible manner could
result in injury or damage to the Product or other property. This Product is not intended for use by children with-
out direct adult supervision. The Product manual contains instructions for safety, operation and maintenance. It is
essential to read and follow all the instructions and warnings in the manual, prior to assembly, setup or use,
in order to operate correctly and avoid damage or injury.
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 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 Nitrotane™ fuel. Nitrotane™ fuels are vigorously tested,
researched and formulated to deliver superior power and engine protection. An LOSR2836 #6 turbo glow plug
has been included and is ideal for this engine. This plug has been designed to deliver both 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.
Carburetor Adjustments
Nitrotec engines come equipped with a precision
slide-valve carburetor. Familiarize yourself with the various
adjustments of the carb. Turning the low or high-speed
needle valves counterclockwise will richen the mixture. Turn-
ing the needle valves clockwise will lean the mixture. Turning
the idle screw clockwise will speed up the idle and vice versa.
The carburetor may be rotated to fit your application by
loosening the cap screw on the side of the crankcase below
it. Although preset at the factory, changes to these settings
will be needed for your model.
Starting settings using a 7mm insert
High-Speed Needle: 4 turns out (counterclockwise) from closed.
Low-Speed Needle: 3 turns out (counterclockwise) from closed.
Do not over-tighten the needles when checking the adjustment. Stop turning clockwise
(closing) immediately when you feel resistance in the needle and begin turning the needles
counterclockwise (open) counting the number of turns from “closed.”
Break-In
Since this is a racing engine manufactured by one of the leading engine manufactures in the world you must
follow the break-in directions included with these instructions. Take your time and you will be rewarded with a
great performing engine that will last for a long time.
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.
Turn on your radio and confirm the throttle is closed. Attach a glow igniter to the glow plug. Place your finger
over the exhaust and turn the engine over with the starter for 1–2 seconds to prime the fuel line. (This should
only be necessary when the engine is cold, do not touch the exhaust pipe when the engine is warm.)
Should the engine become difficult to turn over, 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 and remove the glow plug.
Turn the model upside down and rotate the flywheel to clear out the fuel or put a rag over the top of the head
and turn over on the starter. 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.
Note: Pre-heating the cylinder of the engine with a heat gun helps initial starting easier. Increasing the idle
speed during break-in will help keep the engine running while the needle settings are rich.
©2010 Losi, a Division of Horizon Hobby, Inc.
Printed 03/10
27944
Nitrotec ™ R21 3.5cc Racing Engine
Parts List LOSR2800
LOSR2824