Pontoon Boat Gas Tank Size & How To Increase Fuel Load

Gas tank above tubes on pontoon boat

Pontoon boats are pure luxury on the water. With plenty of deck space for entertaining and superior stability on calm water as standard it is hard to beat a pontoon boat especially when you just want to float on the water. The only problem is many of them have small gas tanks. So, when you want to actually do a bit of boating you need to know how much fuel the boat can hold so you get to where you are going and back again. So how big is a pontoon boat tank and how much fuel does it hold?

Most modern pontoon boats will have a fuel capacity between 20 and 35 gallons, with fuel held in either one or two gas tanks.

Some pontoon boats will have a fuel tank that can hold 24 gallons while another may only hold 6 gallons. Two 6 gallon tanks is also common.

Because pontoon boats are often used on lakes and other inland water bodies, large fuel tanks are not deemed necessary by some manufacturers. Many pontoon boat owners therefore replace an existing tank with a bigger one or will add an additional tank to their boat.

The average capacity of a pontoon boat’s gas tank

Many pontoon boats come with fuel tanks that are insufficient for their owners boating needs. As pontoon boats are designed to give comfort on the water in the form of relaxed recreational boating, and less for actual boat-based activities, some manufacturers tend to hold back on fuel tank sizes.

Pontoon boats can all different sized tanks depending on the size of the boat and the manufacturer who made it. It is not uncommon to see a 6 gallon tank on a pontoon boat or two 6 gallon tanks, especially if you are buying used. When you think of the cost of these boats it is my personal opinion that this is not really good enough on the part of the manufacturers.

Having said that, a large percentage of the new pontoon boats being made now come with gas tanks with a 20 – 35 gallon capacity.

Rant over … back to the problem of 6 gallon tanks.

A typical pontoon boat comes with a baseline 115 hp outboard motor. Though smaller pontoon boats can be fitted with smaller engines and larger boats can have bigger engines, 115 hp for a pontoon outboard motor is the standard.

A 115 hp outboard motor can eat-up 6 to 8 gallons of fuel per hour with a wide open throttle, yet the boat may only have a 6 gallon fuel tank to feed it. Obviously this can cause problems for those pontoon boat owners who actually like to use their boats for anything other than partying. Water activities such as tubing and water skiing eat up a lot of fuel. Hell even if you use you boat for fishing and tend to venture to far off feeding grounds a 6 gallon tank may cause you problems.

One pontoon boat owner had a boat with 2 portable six gallon tanks on the tubes that was completely insufficient for him on one occasion. While on a river his tank ran dry just as a barge was heading straight for him. He had to quickly change tank. Later the same day he ordered a 13 gallon tank with a fuel gauge on it which he mounted on the deck of his boat!

Ideal fuel tank size for a pontoon boat

The ideal fuel reserves for an average 20 –  24 foot pontoon boat should really be no less than 20 gallons. If you can push that up to between 30 gallons and 50 gallons it would be better.

However, 20 gallons of fuel gives your boat more than enough juice to power it for a myriad of activities without you having to ration fuel or sweat over whether you have enough gas to get back home or not.

At the need of the day it really depends more on how and where you use your pontoon boat than the size of it. If you only boat on fairly small waters then a big fuel tank is completely unnecessary. Additionally if use your boat less frequently then having a 30 gallon tank filled with gas sitting over the winter isn’t a great idea.

But, if you like to move your boat around a lot and/or love water sports or just speeding across a lake then you will obviously need bigger fuel reserves.

Pontoon boats are meant to be fun and there is no worse party killer than having to switch off your motor to save on fuel when you don’t want to. Carrying gas cans onboard is also not much of a solution as you will likely have to beach the pontoon or return to the marina to refuel the tank.

Luckily there are solutions available.

Solutions for insufficient fuel capacity

So what is the solution if your pontoon boat has a small fuel tank and you want to do things with your boat that require much more gas than your current tank can carry?

Well, there are actually two simple solutions which I will cover now.

Replace the existing small tank with a bigger one

You can rectify the problem of insufficient fuel storage by simply replacing your tank.

Unless your tank is a reasonable size, say 13+ gallons, I would really be looking to replace it.

If you don’t want to fully replace the gas tank with a bigger one, which can be costly, the cheaper option is to just add another smaller one.

Add an additional tank

Pontoon boat accessories come in all shapes and sizes but not many people think of adding an extra tank to their boat – one accessory that I feel is essential if you want to get the most from your boat (especially if you like to indulge in some pontoon boat party fun).

Modern pontoon boats, and many old ones, will be fitted with 2 tanks instead of one. These days this is the preferred setup for most pontoon boat owners but not all boats come with 2 tanks. And, surprisingly many pontoon boats have tanks that are, in my opinion, simply too small for the boat.

Some boats have portable tanks, usually 6 gallons each, on the tubes that can be removed easily for refilling.  If your pontoon boat does have dual tanks then simply replace one or both of them with bigger tanks to give yourself longer periods on the water.

Many pontoon boat owners will keep one 6 gallon tank as an emergency reserve and put on another 12 – 20 gallon tank, like this one, and use it as the main fuel source.


Different pontoon boats have different sized gas tanks. Most new pontoon boats will have a fuel capacity between 20 and 35 gallons. Most used pontoon boats will not have the same capacity unless the tanks have been upgraded by the current, or previous, owner.

Many boats will have a 6 gallon tank or two 6 gallon tanks.  One 6 gallon tank is unlikely to be enough for most pontoon boat owners unless they are really conservative boaters who merely wish to push their pontoon boat out onto the water to anchor there.

Two 6 gallon tanks is a little better than just one tank, but 12 gallons of fuel still leaves you with some restrictions when it comes to activities you can engage in on your boat.

A 20 gallon tank is the best bet for most pontoon boats as this gives you enough fuel to open up the throttle of your boat, and/or venture further out in the waterways, without having to ration fuel or worry about whether you have enough gas to get the boat back to shore or not.

One solution to low fuel capacity is to replace the boat’s existing tank with a much bigger permanent fuel tank with a fuel gauge on it. A cheaper option is to add an additional smallish-sized tank to the boat making sure the combined capacity of both tanks is enough to fit of your boating needs.

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