TROUBLESHOOTING GUIDE
PROBLEM
CAUSE
SOLUTION
1) Engine does not start
A) Failed glow plug
A) Replace glow plug with a new one
B) Glow Starter not charged and/or faulty
B) Fully charge glow starter and/or replace
C) Engine not being turned over fast enough
C) Use an electric starter to start engine
D) Idle mixture screw set too lean
D) Reset idle mixture to factory setting
E) Old or contaminated fuel
E) Replace with new fuel
F) Engine flooded with too much fuel
F) Remove glow plug and expel fuel from cylinder
G) Faulty fuel tank and/or stopper assembly
G) Check and/or replace fuel tank assembly
H) Air leak in fuel system and/or engine
H) Replace fuel lines and/or tighten all engine bolts
2) Engine does not draw fuel
A) Air leak in fuel system and/or engine
A) Replace fuel lines and/or tighten all engine bolts
B) High Speed Needle Valve fully closed
B) Reset high speed needle valve to factory setting
C) Idle mixture screw set too lean
C) Reset idle mixture to factory setting
D) Fuel lines kinked
D) Check and straighten fuel lines
E) Defective fuel tank
E) Replace fuel tank
3) Engine vibrates excessively
A) Propeller out of balance
A) Balance propeller
B) Engine and/or motor mount loose
B) Tighten motor mounting bolts
4) Engine does not transition
A) Failed and/or wrong type glow plug
A) Replace with new recommended glow plug
B) Old and/or wrong type fuel
B) Replace with new recommended fuel
C) High speed needle valve set too rich
C) Reset high speed needle valve to leaner setting
D) Idle mixture set too lean
D) Set idle mixture richer
E) Idle mixture set too rich
E) Set idle mixture leaner
F) Air leak in fuel system and/or engine
F) Replace fuel lines and/or tighten all engine bolts
G) Propeller too large
G) Replace with one size smaller propeller
5) Throttle barrel does not
A) Throttle servo linkage out of adjustment
A) Adjust throttle linkage to close throttle barrel
close completely
completely.
B) Idle stop screw out of adjustment
B) Turn idle stop screw out until barrel closes
C) Idle mixture screw set too lean
C) Readjust idle mixture screw to factory setting
6) Engine Overheats
A) Engine running too lean
A) Richen high speed needle valve
B) Cowl too restrictive
B) Open larger vents in cowling to allow air to exit
C) Wrong type of fuel used
C) Use fuel with recommended oil content
D) Engine not fully broken-in
D) Allow engine further break-in time
7) Engine stops abruptly
A) Engine running too lean
A) Richen high speed needle valve
B) Piston and sleeve fit worn
B) Return engine to Magnum Engines Service Center
This troubleshooting guide has been provided to help you diagnose and solve most problems that you may encounter with
your Magnum XL .25ARNV or XL .28ARNV engine. Most problems encountered can be solved by carefully following the
problem-cause-solution sections below. If you cannot solve the problem using this troubleshooting guide, please feel free to
contact us at the address or phone number listed.
Magnum Engines Customer Care
18480 Bandilier Circle
Fountain Valley, CA 92728
Phone (714) 963-0329 Fax (714) 964-6236
E-mail: service@globalhobby.com
