Owner’s manual, Troubleshooting, Storage – Master Lock MGH8500AIE User Manual
Page 15: Servicing the engine, Technical service

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OWNER’S MANUAL
TROUBLESHOOTING
WARNING: Only a qualified electrical service person should service
and repair generator. Use only factory approved replacement parts.
POSSIBLE CAUSE
1. Defective capacitor
2. Winding short circuit or loose 
connections
3. Defective rotor diode
4. Loss of residual magnetism
1. Engine speed too low
2. Defective rotor diode
3. Partial short circuit in winding
4. Defective capacitor
1. Engine speed too high
1. Defective rotor diode
2. Electrical load too high
3. Engine not running properly
OBSERVED PROBLEM
No voltage when starting generator with no 
electrical load
Voltage is less than normal voltage with no 
electrical load
Voltmeter reading more than 10% high with 
no electrical load
Voltmeter reading correct with no electrical 
load, but more than 10% low when electrical 
load is added
REMEDY
1. Replace capacitor
2. Check resistance of coils (see Electrical 
Component Specifications,
page 16)
3. Replace both diodes on rotor
4. Apply 12-volt battery to capacitor ter-
minals for 2-3 seconds
1. Set engine speed to 3720 RPM (62 Hz)
with no load
2. Replace both diodes on rotor
3. Check resistance of coils (see Electrical 
Component Specifications,
page 16)
4. Replace capacitor
1. Set engine speed to 3720 RPM (62 Hz)
with no load
1. Replace both diodes on rotor
2. Do not overload generator
3. Contact an authorized engine service 
center
STORAGE
Note: For additional help, visit DESA
International’s technical service web site 
at 
www.desatech.com.
www.desatech.com
Note: See engine owner’s manual for engine troubleshooting.
SERVICING THE
ENGINE
Honda parts and services should be handled 
by your nearest authorized engine service 
firm. Check the yellow pages of your tele-
phone directory under the listing:
Engines Gasoline, Honda
or visit:
www.honda-engines.com
or call Honda direct:
1-800-426-7701
IMPORTANT: Keep generator level while in
storage. Never store generator upside down 
or standing on end.
Note: We supply the engine owner’s manual 
with generator. Refer to that manual for 
questions concerning engine storage. 
WARNING: The muffler be-
comes very hot during operation.
The muffler remains hot for a
while after shutdown. Let engine
cool before storing.
WARNING: Remove all fuel from
fuel tank before storing generator.
Store fuel in approved container.
Store fuel in a well-vented area free
of open flames or sparks.
Use a fuel additive, such as STA-BIL
®
or an
equivalent, when storing generator with fuel 
in fuel tank. This will minimize fuel gum 
deposits from forming in engine. 
Cover and store generator in a clean, dry 
place. Do not expose generator to extreme 
high or low temperatures during storage.
TECHNICAL
SERVICE
You may have further questions about as-
sembling, operating, or maintaining this 
product. If so, you can visit our Technical 
Service web site at 
www.desatech.com
or
contact our Technical Service Department 
at 1-800-858-8501 (English Only). You may 
also write to:
DESA Specialty Products™
ATTN: Technical Service Specialty Products
P.O. Box 90004
Bowling Green, KY 42102-9004
When contacting DESA Specialty Prod-
ucts™, have ready
• Your Name
• Your Address
• Your Phone Number
• Model Number of Product
• Serial Number
• Date of Purchase (Include copy of receipt 
for written requests).
