Magnum XL .25ARNV User Manual

The Magnum XL .25ARNV thru .36ARNV engines are single cylinder, two
cycle engines incorporating ABC piston and sleeve technology for long
life and easy break-in. A dual needle carburetor for precise adjustments is
standard on all four engines. All four engines incorporate a cast aluminum
rear needle valve assembly for safety. The engine was designed by expert
engineers and built by master craftsmen using only the highest quality ma-
terials and CNC machinery. These qualities provide the long life and de-
pendability you have come to expect from an engine of this caliber.
INTRODUCTION
BECOMING FAMILIAR WITH THE MAGNUM
XL .25ARNV thru .36ARNV ENGINES
Before attempting to operate your new engine, please read through this
instruction sheet in it’s entirety. This will help you familiarize yourself
with the features and operation of your new engine. Use the photos below
to identify the major component parts of your new engine.
SPECIFICATIONS
WARNING!
Magnum model engines will consistently give you dependable performance
and reliability and will be a source of satisfaction and pleasure if you fol-
low these instructions as to the engine’s proper and safe use. You alone are
responsible for the safe operation of your engine, so act sensibly and with
care at all times. This Magnum model engine is not a toy. It is a precision
built machine whose power is capable of causing serious injury to yourself
and others if abused, misused or if you fail to observe proper safety pre-
cautions while using it. Please read the safety warnings below carefully.
N Keep spectators, especially small children, at least 20 feet away from
the engine while it is running.
N Mount the engine securely in the airplane or on a suitable engine test
stand to run the engine. Follow the mounting instructions in your kits’ in-
struction manual or on the plans for individual mounting recommendations.
Do not clamp the engine in a vise to test run it.
N Use the recommended size propeller and follow the proper procedure
for mounting the propeller. Use the correct size wrench to tighten the
propeller nuts. Do not use pliers.
N Inspect the spinner, propeller and propeller nut on a regular basis,
looking for any signs of nicks, cracks or loosening.
N To stop the engine, adjust the throttle linkage to completely close the
throttle barrel and therefore cut off the air supply. You can also pinch the
fuel line to stop the engine, but only if it is safely accessible. Do not throw
anything into the spinning propeller or attempt to use your hands to stop
the engine.
N Stand behind the engine while it is running to make any adjustments
to the mixture controls. Do not reach over or around the propeller. Do not
lean towards the engine. Do not wear loose clothing or allow anything to
be drawn into the spinning propeller while the engine is running.
N If you need to carry your model while the engine is running, be con-
scious of the spinning propeller. Keep the airplane pointed away from you
and others at all times while the engine is running.
N Do not use tight fitting cowls or oversized spinners as these can im-
pede airflow over the engine and result in overheating and possible severe
damage to the engine.
INSTALLATION
q Engine Orientation
The Magnum XL .25ARNV - .36ARNV engines can be orientated in any posi-
tion on the firewall. Keep in mind that when the engine is mounted inverted,
carburetor adjustments will need to made differently and the fuel tank may
need to be lowered. (See tank size and orientation to carburetor on next page).
OPERATING INSTRUCTIONS
XL .25ARNV - .28ARNV and
XL .32ARNV - .36ARNV
XL .25 XL .28 XL .32 XL .36
Displacement (cc)
Bore (mm)
Stroke (mm)
Practical R.P.M.
Weight (w/Muffler)
Crankshaft Thread
1/4 - 28 1/4 - 28 1/4 - 28 1/4 - 28
(XL .36A RNV Shown)
Pressure Nipple
Muffler
Exhaust Cone
Carburetor
Prop Washer
Prop Nut
Crankshaft
Thrust Washer
Cylinder Head
Needle Valve
Detent Spring
Needle Valve
Mount
Fuel Nipple
Crankcase
Carburetor Retaining Bolt
Throttle Arm
Muffler Thru Bolt
Fuel
Nipple
Throttle
Arm
Idle Mixture
Screw (inside
throttle arm)
Rotor
Bolt
Fuel
Nipple
Rotor
Bolt
Throttle
Arm
Idle
Mixture
Screw
Idle Stop
Screw
(XL .28A RNV Shown)
(XL .36A RNV Shown)
4.05 4.57 5.26
5.81
17.42
18.5
19.5 20.5
8.5 8.5 8.8 8.8
2,000 - 16,000 2,000 - 16,000
2,000 - 16,000
2,000 - 16,000
11.2
10.8 12.3 12

Magnum XL .25ARNV Specifications

General

Brand	Magnum
Model	XL .25ARNV
Category	Engine
Language	English

Summary

Specifications

Warning!

Becoming Familiar With The Magnum XL.25ARNV thru .36ARNV Engines

Installation

Engine Orientation

Guidance on engine mounting positions and considerations for inverted installations.

Engine Bolts and Firewall Requirements

Specifies requirements for mounting hardware and firewall construction for secure engine installation.

Muffler Installation

Instructions on how to properly mount the muffler to the engine for optimal performance.

Tank Size and Orientation to Carburetor

Recommendations for fuel tank size and positioning relative to the carburetor for consistent fuel flow.

Carburetor Installation

Steps for correctly installing the carburetor onto the engine crankcase, ensuring a proper seal.

Rear Needle Valve Installation

Procedure for mounting the rear needle valve assembly and connecting the fuel pickup line.

Needle Valve Extension

How to install an extension for the high speed needle valve for easier adjustment.

Idle Stop Screw and Rotor Bolt

Information on the idle stop screw for throttle barrel closure and rotor bolt function.

Propeller Installation

Detailed steps for safely and correctly installing the propeller onto the engine crankshaft.

Propeller, Fuel & Glow Plug

Propeller Recommendation

Guidance on selecting the correct propeller diameter and pitch for optimal engine performance.

Glow Plug Recommendation

Advice on choosing the appropriate glow plug heat range for reliable engine operation.

Fuel Recommendation

Recommended fuel types, nitro content, and lubricant percentages for break-in and normal use.

High & Low Speed Needle Valves

Adjusting air/fuel mixture for optimal engine performance at different throttle settings.

Starting Procedure

Step-by-step instructions for starting the engine, including methods for electric and hand starting.

Break-In Procedure

Detailed steps for properly breaking in ABC engines to ensure longevity and performance.

Setting The Mixture

Setting the High Speed Needle Valve

Procedure for fine-tuning the high speed needle valve for optimal running performance.

Setting the Low Speed Needle Valve

Procedure for fine-tuning the low speed needle valve for smooth throttle transitions.

Maintenance

Service

Our Recommendations

Fuel

Recommended fuel brands and types for break-in and normal operation of Magnum engines.

Fuel Tank

Recommendation for a specific fuel tank size suitable for the XL .25ARNV and .28ARNV engines.

Glow Plug

Recommended glow plug model for easy starting and excellent transition.

Propeller

Recommended propeller size for breaking in the engine and general guidance.

Glow Driver

Recommended glow starter for heating glow plugs, featuring a meter and charger.

Motor Mount

Recommended motor mount type for secure installation on a plywood firewall.

Quick Start

Engine Preparation

Steps for preparing the engine before the first start, including mounting and muffler installation.

Engine Starting

Procedures for initial engine starting, covering both hand and electric starter methods.

Troubleshooting Guide

Magnum XL.28ARNV Parts Break Down

Magnum XL.28ARNV Parts List