Important: Read the owner’s manual thoroughly to understand all instructions, cautions, and warnings before using this equipment. If any section of the manual is not understood, contact your nearest Independent Authorized Service Dealer (IASD), or contact Generac Customer Support at 1-888-436-3722 (1-888-GENERAC), or Generac.com with any questions or concerns.

How do I use the choke on my portable generator?

This article provides an overview of the choke on a portable generator, what it is, what it does, and how to use it. It also explains common PowerDial positions and what to check if the generator starts with the choke on but shuts down when moved to the RUN position.

Environment

This article applies to Generac portable generators with a manual choke or an integrated choke control. Some PowerDial models do not have a separate choke lever because the choke is controlled by the dial.

Note: All Generac portable generators with electronic fuel injection (EFI) do not have a choke mechanism.

Understanding the choke on a portable generator

The choke helps regulate the air-fuel ratio for easier starting, especially when the engine is cold, by restricting airflow from the air filter to the carburetor.

What the choke does

Choke ON, START, or closed:

• Limits air entering the engine, enriching the fuel mixture for cold starts.

Choke OFF, RUN, or open:

• Allows more air, creating a balanced air-fuel mixture for normal operation once the engine is warmed up.

How to use the choke effectively

The procedure below provides a basic understanding of how to use the choke. However, startup procedures, choke design, and choke location may vary by model. For model-specific steps, refer to the owner’s manual. For help finding a copy of the owner’s manual, see Where can I download a user manual for my Generac portable generator?.

Starting a cold engine

Starting a warm engine

Note: This article does not show every choke style used on Generac portable generators. Always check the owner’s manual for the correct choke position, starting steps, and PowerDial operation for the specific generator model.

Troubleshooting

• If the engine sputters or stalls after starting, open the choke slightly to allow more air, then gradually move it to the OFF or RUN position as the engine smooths out.
• If the engine is hard to start or runs rough, confirm the choke is in the correct position for the engine’s temperature.
• If the engine only runs with the choke ON, in the START position, or in position 1 on some PowerDial models, and then sputters or shuts down when moved fully to RUN or position 2, the engine may not be getting enough fuel for normal operation. This can happen when the carburetor is dirty or restricted, especially after old fuel has been left in the generator. For more information, see How do I clean my portable generator's carburetor?
• Do not continue operating the generator in the choke or START position after the engine has warmed up. The generator should run in the RUN position during normal operation.

Common issues related to the choke

Flooding the engine

What it is

• Flooding happens when the engine has too much fuel and insufficient air to ignite it, causing the engine to stall or fail to start.

How it relates to the choke

• Leaving the choke in the ON, START, or closed position for too long can flood the engine because the choke reduces the amount of air entering the engine.

How to avoid it

• Move the choke to the OFF or RUN position shortly after the engine starts running. If the engine becomes flooded, wait a few minutes, then try starting it again with the choke OFF.

Stuck choke

What it is

• A choke can get stuck in the ON or OFF position due to mechanical issues or dirt buildup.

How the choke affects the engine

• A stuck choke in the ON position can make the engine run too rich, meaning too much fuel and not enough air, causing poor performance or flooding.
• A stuck choke in the OFF position can make it difficult to start a cold engine.

What to do

• Check the choke mechanism for dirt or debris and clean it if necessary. If it remains stuck, the generator may require service from an Independent Authorized Service Dealer (IASD). For help finding service, see How can I find a Generac service dealer in my area?

Dirty or restricted carburetor

What it is

• A dirty or restricted carburetor may prevent the engine from getting enough fuel when the choke is open.

How it relates to the choke

• If the generator runs with the choke ON or in the START position but stalls in RUN, the choke may be compensating for a fuel delivery issue. This is commonly related to the carburetor, especially after long storage or use of old fuel.

What to do

• Check the fuel condition and consider cleaning the carburetor. For more information, see How do I clean my portable generator's carburetor?

Types of choke designs for Generac portable generators

Below are some of the common choke mechanisms used with Generac portable generators. The images and descriptions are examples and may not match every model.

Note: All Generac portable generators with electronic fuel injection (EFI) do not have a choke mechanism.

Using the choke with the Generac PowerDial

PowerDial designs vary by model. Some PowerDial controls show OFF, RUN, and CHOKE. Other PowerDial controls, including RS5500 and RS7000E models, may use START, RUN, and STOP positions or numerical positions instead of a separate choke lever.

The three PowerDial positions generally function as follows:

1. START, CHOKE, or position 1: Used for starting a cold engine. On applicable PowerDial models, this opens the fuel valve and activates or closes the choke.

2. RUN or position 2: Used for normal operation after the engine starts. In RUN, the choke is OFF or open, and fuel flow remains ON.

3. OFF, STOP, or position 3: Used to stop the engine. On applicable PowerDial models, this also shuts off fuel flow.

After starting the generator, gradually move the dial from START or CHOKE toward RUN. If the engine falters while moving toward RUN, move the dial slightly back toward START or CHOKE until the engine smooths out, then gradually move it fully to RUN.

Note: If the generator continues to run only in START, CHOKE, or position 1 after warming up, and stalls when moved to RUN or position 2, this is usually not a normal choke condition. Check for fuel, carburetor, or maintenance issues.

Using the choke on standard Generac portable generators

C. The full choke position (ON) is to the left.