How to Start a Dual Fuel Generator Step by Step

Before you start: safety and setup

A few minutes of setup prevents most problems. It also keeps you safe, because every generator makes carbon monoxide (CO), an odorless gas that can be fatal.

Run the generator outdoors only, well away from windows, doors and vents. Never run it in a garage, even with the door open. Many dual fuel models include a CO shutoff sensor, such as the Westinghouse iGen12000DFc and iGen5000DFc, but a sensor does not replace good placement. Also keep a battery-powered CO alarm inside your home.

• Set the generator on firm, level ground under a dry, open-sided cover if it might rain. Never use it in the rain or snow without protection.
• Keep it clear of anything that burns, and keep children and pets away from the hot muffler.
• Check the engine oil with the unit level. Many generators ship without oil, and most have a low oil shutdown that will stop the engine from starting.
• Make sure nothing is plugged in and any main breaker on the generator is off or any load switch is in the off position.
• Wear hearing protection if you will stand near a larger unit for long. Some larger models on our page list 64 to 74 dBA.

How to start on gasoline, step by step

Gasoline is the default fuel on most dual fuel generators, and it is often the one you use for the first run. Use fresh gasoline, and never fill the tank while the engine is running or hot. Spilled fuel on a hot engine can ignite.

Follow these steps in order.

• Disconnect any propane hose from the generator so the fuel source is clear.
• Fill the tank with fresh gasoline, leaving room for expansion, and wipe up any spill. Check the fuel gauge if your unit has one.
• Set the fuel selector switch to gasoline. Some units use a front-panel switch, others use a knob or a button.
• Turn the fuel valve to on, if your model has a separate petcock.
• Move the choke to closed for a cold engine, if your model has a manual choke. Many inverter models manage this automatically.
• Start the engine. Use the pull cord (recoil), turn the key, press the button or use the key fob, depending on the model.
• As the engine catches, move the choke gradually to run. Let the engine settle for a minute or two.
• Plug in your loads one at a time, starting with the largest, and watch for a steady output.

How to start on propane

Propane has a few extra steps because you are connecting a pressurized tank. Check that the hose and tank valve are in good shape before you begin. Never use a flame to check for leaks. Instead, brush soapy water on the connections and look for bubbles once the gas is on.

The first part is the same as gasoline, so check the oil and set up outdoors. Then do this.

• Place the propane cylinder upright on a stable surface, outside and away from the exhaust.
• Connect the supplied hose or regulator kit to the cylinder and to the generator's propane inlet. Hand-tighten fittings as directed in the manual.
• Set the fuel selector to propane.
• Open the cylinder valve slowly. Check connections with soapy water for bubbles, and shut the valve at once if you find a leak.
• Start the engine using the method your model offers. A choke is usually not needed on propane, but check the manual.
• Let the engine run for a minute or two before you add loads.

Switching fuels and what changes

Many dual fuel models let you change fuel with a switch. The safest habit is to shut the generator down, set the selector, then restart. Some manuals allow switching while running, so follow yours rather than guessing.

Expect lower output on propane. Our best dual fuel generator page notes this on units that list both figures. The table below shows the published running watts for three Westinghouse models.

Notes for Champion, Firman and other brands

We compare published specifications, so we cannot give a button-by-button sequence for every model. The steps above fit most dual fuel units. For the Champion 7850 or other Champion and Firman models, confirm the exact order in your manual, including where the fuel selector sits and whether it has a choke, a key switch or a remote key fob.

Start type matters for how the first step feels. The Westinghouse iGen12000DFc lists remote electric start and ships with a key fob, a battery, a 12V charger and a propane regulator kit. The DuroMax XP13000HX lists a push-button start and a front interface for changing fuel type. A unit with only a recoil pull cord will need a firm, steady pull instead.

If you are new to a unit, practice in daylight before a storm. A first run on propane is a good habit, since propane leaves less residue in the carburetor than old gasoline.

If it will not start

Most no-start problems are simple. Work from the easiest fix to the hardest, and turn the engine off before touching any part of it.

• Low oil shutdown: top the oil up to the mark on a level surface.
• Empty fuel: check the gasoline level or the propane cylinder, and make sure the valve is open.
• Wrong selector setting: confirm the switch matches the fuel you connected.
• Old gasoline: stale fuel is a common cause of hard starting. Drain it and refill with fresh fuel, or try propane.
• Dead battery on electric start models: use the recoil starter if your model has one, or charge the battery.
• Tripped CO sensor: move the unit to open air and restart. If it keeps shutting down, stop using it and have it checked.

Picking a model that is easy to start

If you are still choosing, think about how you will start it under stress. Remote and push-button starts are convenient in cold or wet weather. Our best generator page covers the wider field, and the dual fuel page lists start type, CO sensor and running watts side by side.

Also size the unit to your loads. Add up the running watts of what you need and leave a margin, since propane output is lower than gasoline.

Frequently asked questions

Can I leave propane connected when I run on gasoline?

It is better to disconnect it, or at least close the cylinder valve, so the fuel source is clear and you avoid a leak. Check your manual for its guidance.

How long should I let the generator warm up?

A minute or two at no load is usually enough. Then add your loads one at a time, largest first.

Do I need to ground a portable generator?

Requirements vary by model and use. If you connect it to a house through a transfer switch or interlock kit, have a licensed electrician do the install and follow your manual.

Why does my generator start on gasoline but not propane?

Check the cylinder valve, hose connections and fuel selector first. A nearly empty cylinder or a loose fitting is the usual cause.