Xray NT18 0.8cc Instruction And Safety Manual - page 13
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Each engine is shipped from the factory with all carburetor settings set to a standard position.
A nitro-powered engine requires careful break-in the first time the engine is used to allow the internal parts to achieve proper
operating clearances. This is especially true of the piston/cylinder, crankshaft, and conrod. Pay close attention during the initial
break-in period; this process is very important to achieve the best engine performance, reliability, and lifespan.
The proper way to break in this nitro engine is to "heat cycle" the engine with short periods of running followed by cooling down
periods. Heat cycling allows the engine to heat up to its optimum operating temperature, allowing the components to "wear in" to
each other properly. During the running time, the engines should be run only SLIGHTLY rich at the top end; overly rich mixtures
and cold temperature break-in will lead to premature wear and failure of the piston & sleeve and other engine components.
First, install the engine in the car, then break in the engine by performing the following steps:
1. Keep the carburetor factory settings; do not adjust.
2. Fill the fuel tank and "dry-start" the engine for 2-3 seconds without applying the glowplug starter, and with the carburetor
in the "idle" position. This primes the fuel lines and allows the fuel to reach the engine.
3. Apply the glowplug starter and start the engine with a starter. We strongly recommend using the #104300 HUDY Micro Start-Box.
4. Allow the engine to idle for a short time so the engine warms up.
5. Run the engine for 5~8 minutes, varying the throttle setting, without exceeding 1/2 throttle.
The engine should run cleanly, and only SLIGHTLY rich at the top (noted by a very slight "burbling"). If the engine runs
very crisply with high temperature and hard acceleration, it is probably running too lean; turn the main needle CCW
slightly to richen the mixture very slightly at the top.
6. Stop the engine and allow it to cool down completely. Make sure the piston does not get stuck at top of the cylinder
(TDC); rotate the flywheel to move the piston to the bottom of the cylinder (BDC).
7. Run the engine for several more heat cycles:
• 5~8 minutes up to 2/3 throttle, then complete cool-down.
• 5~8 minutes up to 3/4 throttle, then complete cool-down. (During the running, start to lean the main needle so it
runs only very slightly rich – less than before – on top.)
• Run through a full tank of fuel up to full throttle, adjusting the main needle so the engine runs cleanly at high RPM.
Do not run the engine at high RPM without load; that is, don’t pick the car off the ground and run the engine hard. The
engine will overheat without the airflow over its cooling head, damaging the engine components.
ENGINE BREAK-IN