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how to drain gasoline from your generator

Since old gasoline can cause starting problems, knowing how to safely drain generator gasoline is an important part of keeping your generator in top condition.

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Draining your portable generator’s fuel tank is one of the most reliable ways to store your generator and ensure its longevity. Help extend the life of your generator, avoid costly maintenance, and most importantly, be ready for the upcoming season.

Since old gasoline can cause starting problems, knowing how to safely drain generator gasoline is an important part of keeping your generator in top condition.

do I need to drain the petrol from the generator?

If you use fuel stabilizer, you don’t have to worry about gasoline in your generator during winter storage.

However, draining the gasoline from your generator is the surest way to prevent fuel-related problems during long-term generator storage.

If you’re wondering if it’s necessary to drain the gasoline from your generator, the answer is yes. This is an important aspect of proper generator maintenance that can effectively extend the service life and optimal operating rate of the equipment while minimizing potential repair costs.

Because over time, gasoline left in a generator can deteriorate and form a sticky resin, commonly known as varnish. This substance can cause a range of operating problems, from a clogged carburetor that reduces generator performance, to a serious failure that renders the generator unusable. It can also lead to corrosion of the generator housing and system.

In general, if you anticipate that your generator will be idle for an extended period of time (usually 30 days or more), China BISON strongly recommends draining the gasoline from the generator.

Below, China BISON will take a closer look at the step-by-step process of running out of gas in a generator, taking you through each stage carefully and safely.

How to Drain the Gas from Your Generator-Specific steps

how to drain gasoline from your generator

The risks of improper handling of gasoline cannot be overstated, so all fuel and gas venting steps need to be performed carefully. Below, China BISON will guide you through common methods of draining fuel from a generator.

Turn off the generator: First, make sure the generator is turned off and disconnect all connections. Then let it cool for a while and then move the generator set to a well-ventilated area to ensure safety during the process.

Open the gasoline cap: Unscrew the fuel tank cap to promote air circulation in the gas tank.

Locate the fuel tank and fuel lines: Make sure you can easily reach the fuel line. If there is a plastic cover in the way, carefully remove it.

Close fuel valve: Before disconnecting the fuel line, turn the fuel valve to the “off” position.

Disconnect fuel line: Locate the clamp holding the fuel line that is not connected to the tank. Carefully remove the clamp and disconnect the tube from the fuel valve.

Prepare container: Place a container next to the generator. Place the disconnected end of the fuel line into the container. Tilt the generator slightly so all the fuel flows to one side and out of the lines.

Open the fuel valve: Once most of the fuel is gone, turn the fuel valve back to the “open” position to drain any remaining fuel.

Reconnect the fuel line: Carefully reconnect the fuel line, making sure it is secure. If necessary, close the gas tank lid and reinstall any caps or housings.

Locating the carburetor: Consult your generator manual to locate the carburetor. Remove the bolts from the carburetor and allow any remaining fuel to drain into a container. Use pliers to place the bolt back on the carburetor and tighten it securely.

Draining gasoline from non-inverter or open-frame generators
  • Secure the bolt: Use pliers to reattach the bolt to the carburetor, making sure it is secure.


Draining the generator prior to storage is one of the safest ways to keep your equipment trouble-free while in storage. It will prevent fuel-related issues that will prevent your generator from starting or, worse, forcing you to perform expensive maintenance or repairs.

If you’re a bit technical, you can drain the generator using a drain or fuel line. Also, you can use an external fuel transfer pump which is easier than the previous method.

Welcome to BISON generator manufacturer to learn more about the use of generators.

drain gasoline from generator FAQ

If the fuel is still fresh, the drained fuel should be stored for later use. However, if the fuel spoils, be sure not to dispose of it on the ground, in drainage systems, or any other body of water.

To prevent fuel degradation, all you have to do is add the correct fuel stabilizer to your storage container.

However, you can't just dump the fuel wherever you want because the liquid is still flammable and toxic. You will need to contact your local authorities who will direct you to the appropriate dump site.

Removing the generator side cover and fuel line or unscrewing the carburetor drain screw can be overwhelming for most people. Therefore, running the generator until the gas runs out is the easiest and safest option.

Like gasoline and diesel, which require stabilization or drainage before storage due to oxidation, all motors running on liquid fuels require the same antifreeze steps. Thankfully, propane generators are an exception and do not require draining or stabilization.

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