2023 150 MONTAUK Fuel Tank Fitment

[Saint]

I need advice about choosing an aftermarket fuel tank to use on a 2023 150 MONTAUK

I see there are 18-gallon and 22-gallon Moeller [on-deck] fuel tanks that are specifically meant for a 2023 150 MONTAUK. However, I’d find it very surprising for either to fit under the console seating without modifying the space.

[jimh]

I see there are 18-gallon and 22-gallon Moeller [on-deck] fuel tanks that are specifically meant for a 2023 150 MONTAUK.

I very much doubt that when Moeller created their 18-gallon and 22-gallon molded on-deck fuel tanks they designed them specifically for a 150 MONTAUK. The actual situation that would have been far more likely was that Moller designed the tanks to be able to fit under the classic reversible pilot seat that was commonly used on the classic MONTAUK 17 model.

If you are concerned about the height and clearance on your boat, you should be able to get the tank dimensions from the manufacturer and then compare them to measurements you take from your boat. This should determine if the tanks will fit.

[jimh]

For more background on the Moeller on-deck fuel tanks for Boston Whaler boats, see this article, also in THE GAM:

The MOELLER 24-gallon White On-deck Fuel Tank for Boston Whaler Boats
https://continuouswave.com/forum/viewtopic.php?f=4&t=5807

[jimh]

Another consideration with these larger capacity fuel tanks: you will always be adding fuel to them while they are on the boat. You cannot really call them portable tanks, as they are more-or-less fixed in place on the boat with regard to being able to re-fuel.

If the boat is not kept on a trailer, then getting fuel will necessitate going to a fuel dock, and that means paying marine fuel prices. With 6-gallon tanks, you can take the tank to a highway fuel station and still be able to carry it (with fuel in it) back to the boat, in most cases.

[Saint]

Great! Thank you for the input.

The boat is currently in a marina - so having to unload and load the gas tank is no longer a step for me. While it was convenient to remove the existing tank, it was also quite a bit to carry around once at full capacity.

Thank you for sharing info on the 170 Moeller installation. At this point I think it just be feasible to measure Moeller tank and space under pilot seat to see if it will even fit.

With that said:

Q2: are there any tips or tricks to extend the range of the 150 MONTAUK?

Fo example, strapping a 6-gallon tank somewhere in the aft near the pilot seat

I would like to hear creative solutions.

[jimh]

Adding a second on-deck fuel tank could be a way to extend the range of the boat without refueling. An important consideration for a second on-deck fuel tank will be how the fuel supply hose connects to the engine.

In the old days, engines of modest horsepower would typically have a fuel fitting on their cowling or mounting bracket. The fuel hose from the fuel tank would terminate in a mating fitting. That arrangement allowed having a second fuel tank that could be quickly connected to the engine in place of the primary fuel tank.

Modern engines often do not have a fuel hose connector; they just expect the fuel hose to be permanently connected at the engine.

If your 15-footer is rigged with an engine that has a detachable fuel hose, then rigging a second tank will be simple.

If your 15-footer is rigged with an engine that has a fixed hose connection for the fuel line, the rigging will be more complex. You will need to have a fuel valve that selects which tank will feed the engine.

Also, fuel endurance may be greater that human endurance aboard a 15-footer for continuous underway operation.

[Saint]

jimh—I much appreciate for your insight.

[jimh]

Also, if the fuel hose connection to the engine is not done with a removable connector, you could install an in-line connector at the fuel tank end of the hose, and have a mating connector on the both the primary and secondary fuel tanks. In this way you would use one fuel hose (and primer bulb and inline fuel filter) and move it between two fuel tanks.

The older-style Mercury Marine fuel connector might be useful for this.

Fig. 1. Attach this female fitting to each fuel tank using the brass elbow.

mercury-female-fuel-connector.jpg (27.42 KiB) Viewed 25453 times

Fig. 2. Attach this male fitting to the fuel hose coming from the engine.

mercury-male-fuel-connector.jpg (21.19 KiB) Viewed 25453 times

Here are links to sources for these fittings:

https://thmarinesupplies.com/products/mercury-male-fuel-connector
https://thmarinesupplies.com/products/mercury-female-fuel-connector

You may be able to find knock-offs at lower prices on Amazon.

Many years ago I had a 1976 Mercury 50-HP engine that used this fuel fitting. It was a very good fuel fitting. The fit was excellent and never leaked a drop of fuel. These fittings are made of metal and will last forever.

Using one hose for both tanks means there won't be redundancy in the hose (or the primer bulb). If a problem in the hose stops the engine from running, you won't fix it by changing to a different tank.

[Joel]

I have a 2025 [presumably means a 2025 150 MONTAUK]. I would like to change [the fuel tank from some unspecified current capacity] to a larger [capacity, perhaps to hold] 15, 18, or 22-gallons. I don’t know which [of these three larger capacity 15, 18, or 22-gallon fuel tanks] will fit under [the pilot seat of my 2023 150 MONTAUK].

[jimh]

I don’t know which [of these larger capacity 15, 18, or 22-gallon fuel tanks] will fit under [the pilot seat of my 2023 150 MONTAUK].

I also don't know which of those three tanks will fit under the seat on your boat, but I will offer you the same advice that I gave the originator of this thread in my initial reply in the second post in the thread:

Here is the solution:

• measure the height, width, and depth of the space under the seat where you want the fuel tank to be located;
• compare those dimensions with the published dimensions from the manufacturer of the three fuel tanks you are interested in buying;
• add additional room for the height to allow for the fuel hose connection to be made without interference;
• also consider the location of the fuel tank fill inlet so it will be unobstructed and easy to access for refueling; usually the tank is oriented so the fuel fill inlet extends aft and is not under the seat;
• select the tank that best fits and has the larger capacity you most want.

Actually measuring the space yourself and then deducing which fuel tanks of the three capacities you have listed will fit is going to be a better method for you to invest in buying a new thank than for you to rely on someone else to figure out the fitment of those tanks. Part of the problem is you don't specify the manufacturer of the three tanks--you mention only by their capacity--so there is no way for a reader to know the dimensions of the three tanks you are asking about.

[Joel]

[The steps described by jimh] are my next steps.

The [capacity of the] OEM fuel tank on a 150 MONTAUK one is not large enough for a long day of running the engine, and the tank has to be unstrapped to be filled. The fill opening and the [fuel tank level indicator gauge are located] under the seat and cannot be accessed without moving the tank. Overall the OEM 12-gallon fuel tank is a very poor design.