1. Introduction
This manual provides essential information for the safe and efficient operation, maintenance, and troubleshooting of your Firman Hybrid Series H03651 Dual Fuel Generator. Please read this manual thoroughly before operating the generator to ensure proper usage and to prevent injury or damage.

Figure 1: Firman Hybrid Series H03651 Dual Fuel Generator, showcasing its robust design and control panel.
2. Safety Information
WARNING: Carbon Monoxide Hazard
Generators produce carbon monoxide, an odorless, colorless gas that can kill you. Always operate the generator outdoors in a well-ventilated area, far away from windows, doors, and vents. Never operate the generator inside a home, garage, basement, crawl space, or any other enclosed area.
Ensure proper grounding of the generator before operation. Keep children and pets away from the generator during operation.
3. Components Overview
Familiarize yourself with the key components of your generator:
- Control Panel: Houses the fuel selector switch, outlets, and data minder.
- Fuel Selector Switch: Allows selection between gasoline and liquid propane (LPG).
- Outlets: Various outlets including 120VAC 30A, 120VAC 30A RV, and 120VAC 20A GFCI.
- Engine: Firman 4-stroke, 208 CC, 7 HP engine.
- Wheels: 8-inch flat-free tires for portability.
- Handle: U-shaped paddle handle with ergonomic grip for easy transport.
- Data Minder: Digital display for tracking volts, hertz, and hours of runtime.

Figure 2: Close-up view of the generator's control panel, showing the fuel selector switch and various power outlets.

Figure 3: The generator's durable frame and 8-inch flat-free wheels, highlighting its portability.
4. Setup
- Unpacking: Carefully remove the generator and all accessories from the packaging.
- Wheel Kit and Handle Assembly: Attach the wheels and handle according to the instructions provided in the separate assembly guide. The generator includes 8-inch never-flat wheels and a U-shaped paddle handle for easy maneuverability.
- Add Engine Oil: Before first use, add the provided engine oil to the oil reservoir. Ensure the oil level is correct using the dipstick. Running the engine without sufficient oil will cause severe damage.
- Connect Battery (for Electric Start): Connect the battery terminals. Ensure correct polarity (red to positive, black to negative).
- Fueling:
- Gasoline: Fill the fuel tank with unleaded gasoline. The tank has a 5-gallon capacity.
- Propane (LPG): Connect a propane tank to the LPG inlet using the provided hose and regulator.
5. Operating Instructions
5.1 Fuel Selection
Your Firman H03651 generator is a dual-fuel unit, capable of running on either gasoline or liquid propane (LPG). Use the fuel selector switch on the control panel to choose your desired fuel source.
5.2 Starting the Generator
Ensure the generator is on a level surface and all electrical loads are disconnected before starting.
- Select Fuel: Turn the fuel selector switch to either the 'Gas' or 'LPG' position.
- Open Fuel Valve: If using gasoline, ensure the fuel valve is open. If using LPG, ensure the propane tank valve is open.
- Choke: Move the choke lever to the 'Choke' position (if the engine is cold).
- Start Engine:
- Electric Start: Press and hold the electric start button until the engine starts.
- Recoil Start: Firmly pull the recoil starter handle until the engine starts.
- Choke Adjustment: Once the engine starts, slowly move the choke lever to the 'Run' position.
- Connect Loads: After the engine has run for a few minutes and stabilized, you can connect your electrical devices to the appropriate outlets.
5.3 Stopping the Generator
- Disconnect Loads: Disconnect all electrical loads from the generator outlets.
- Turn Off Engine: Move the engine switch to the 'OFF' position.
- Close Fuel Valve: If using gasoline, close the fuel valve. If using LPG, close the propane tank valve.
6. Maintenance
Regular maintenance is crucial for the longevity and optimal performance of your generator.
- Oil Changes: Check engine oil level before each use and change oil regularly as specified in the full owner's manual.
- Air Filter: Inspect and clean the air filter periodically. Replace if damaged.
- Spark Plug: Inspect and clean the spark plug as needed. Replace if worn.
- Fuel System: If storing the generator for an extended period, drain the gasoline or use a fuel stabilizer to prevent carburetor issues. Propane stores longer and is a cleaner burning fuel.
- Cleaning: Keep the generator clean and free of debris. Outlet covers help protect against moisture and dust.
- Spark Arrester: The Whisper Series muffler includes a USDA-approved spark arrester. Inspect and clean it regularly to prevent fire hazards.
7. Troubleshooting
If your generator encounters issues, refer to the following general troubleshooting tips. For detailed solutions, consult the comprehensive owner's manual.
- Engine Not Starting: Check fuel level, ensure correct fuel selection, verify battery connection (for electric start), check spark plug, and ensure choke is set correctly for a cold engine.
- No Power Output: Check circuit breakers on the control panel. Ensure all connections are secure.
- Engine Runs Rough: Check fuel quality, air filter cleanliness, and spark plug condition.
- CO Alert: If the CO Alert system activates, immediately move the generator to a well-ventilated outdoor area and allow it to cool down. Do not operate until the alert clears.
8. Specifications
| Feature | Specification |
|---|---|
| Brand | Firman |
| Model Name | H03651 |
| Starting Watts (Gas) | 4550 Watts |
| Running Watts (Gas) | 3650 Watts |
| Starting Watts (LPG) | 4100 Watts |
| Running Watts (LPG) | 3300 Watts |
| Engine Type | 4 Stroke, 208 CC, 7 HP |
| Fuel Type | Gasoline / LPG |
| Tank Volume | 5 Gallons |
| Run Time | Up to 14 hours on 5 gallons at 50% load |
| Ignition System | Electric Start and Recoil Start |
| Total Power Outlets | 4 |
| Item Weight | 119.5 Pounds |
| Product Dimensions | 27.9"L x 18.1"W x 20.5"H |
9. Warranty and Support
The Firman Hybrid Series H03651 Dual Fuel Generator is backed by a Three-Year Warranty. For any questions, technical assistance, or warranty claims, please contact Firman customer service.
Customer Service: 1-844-FIRMAN1 (1-844-347-6261)
You can also visit the official Firman Power Equipment website for more information: firmanpowerequipment.com
10. Official Product Video
Watch this official product video for a visual overview of the Firman Hybrid Series Dual Fuel Generators, including features and benefits.
Video: An official overview of the Firman Hybrid Series 3650/4550 Watt Dual Fuel Generator, detailing its features, fuel options, engine, portability, and compliance.







