Product Manual
Table Of Contents
- Section 1: Introduction and Safety
- Section 2: General Information
- Section 3: Operation
- Pre-start Checklist
- Manually Starting the Unit
- AUTO (Remote) Starting the Unit
- Wet Stacking
- Cold Weather Operation
- Using a Booster Battery or Charger (if equipped)
- Generator Output Connections
- Generator Cam Lock Connections (If Equipped)
- Using the Voltage Selector Switch
- Fine Voltage Adjustment
- Voltage Regulator
- Achieving 240V Three-Phase in 208V Three-Phase (Parallel Low Wye) Configuration
- Customer Convenience Receptacles
- Main Circuit Breaker
- Transfer Switch
- AUTO Exercise Timer
- Shutting Down the Unit
- Emergency Stop Switch
- Idle Switch
- Using the ECU Override Switch
- Towing the Unit
- Lifting the Unit
- Section 4: Maintenance
- Section 5: Troubleshooting
- Section 6: Wiring Diagrams and Service Log
- Wiring Diagram - 3 Position AC Box
- Wiring Diagram - 4 Position AC Box
- Wiring Diagram - Receptacles
- Wiring Diagram - Engine Heater
- Wiring Diagram - Wiring Buck (If Equipped)
- Wiring Diagram - Power Zone PMG
- Wiring Diagram - Power Zone Control Box
- Wiring Diagram - Trailer Lights
- Wiring Diagram - Brake Wiring
- Wiring Diagram - 12V Battery Charger
- Wiring Diagram - Power Zone Low Oil Level (If Equipped)
- Service Log
ii Owner’s Manual for MDG25IF4
Use this page to record important information about your Mobile Generator
Record the information found on your unit data label on this
page. See
Unit and Serial Number Locations.
Engine and generator serial numbers are located on separate
data plates affixed to the engine and generator respectively.
When contacting a Generac Mobile Products Authorized
Service Dealer (GMP ASD) about parts and service, always
supply the complete model number and serial number of the
unit.
Operation and Maintenance: Proper maintenance and care of
the generator ensures a minimum number of problems and
keeps operating expenses at a minimum. It is the operator’s
responsibility to perform all safety checks, to verify that all
maintenance for safe operation is performed promptly, and to
have the equipment checked periodically by a GMP ASD.
Normal maintenance, service and replacement of parts are the
responsibility of the owner/operator and, as such, are not
considered defects in materials or workmanship within the
terms of the warranty. Individual operating habits and usage
may contribute to the need for additional maintenance or
service.
Unit Model Number
Unit Serial Number
Engine Model
Number
Engine Serial
Number
Generator Model
Number
Generator Serial
Number
Date Purchased
(000394)
WARNING
Breathing diesel engine exhaust exposes you
to chemicals known to the State of California
to cause cancer and birth defects or other
reproductive harm.
• Always start and operate the engine in a
well-ventilated area.
• If in an enclosed area, vent the exhaust to
the outside.
• Do not modify or tamper with the exhaust
system.
• Do not idle the engine except as necessary.
For more information go to
www.P65Warnings.ca.gov/diesel.
(000393a)
WARNING
CANCER AND REPRODUCTIVE HARM
www.P65Warnings.ca.gov.










