CONTINUOUSWAVE

Q1: where can I purchase a replacement, metal, twist-on gas cap for a 12-gallon, metal, on-deck fuel tank that was original equipment used on my 1988 Montauk 17?

Typically in 1988 a Boston Whaler MONTAUK 17 boat would have left the factory without being rigged with an engine. The dealer would most likely sell the customer an engine and rig the boat with the engine and fuel tank. If you were the original buyer, check with the selling dealer, and ask them for the brand of tank they used.

Bring the tank with you and visit a supply store that caters to the farming sector, like these:

Tractor Supply
Southern States

When I purchased the boat the tanks were included , they are similar to mercury metal tank twist-on caps but 12 gallon not 6 , I understand that they were original equipment on some of the Montaulk’s in the 80’s. I don’t have a picture because it’s covered until the spring.

Kend wrote:When I purchased the boat the tanks were included...

There is no one trying to dispute that the fuel tanks were on the 1988 MONTAUK. 17 boat when you purchased the boat, which I am presuming you mean that you took delivery of a new boat from a Boston Whaler dealer.

Maybe I was not clear in what I was trying to convey, so l will try again:

The notion that the fuel tanks were on the boat when you bought the boat DOES NOT mean that Boston Whaler put them on the boat when it left the factory, UNLESS there was a specific option available in c.1988 to get the fuel tank from Boston Whaler.

In 1988 Boston Whaler was not typically providing boats to its dealers with the engine already installed, rigged with remote controls, and connected to a fuel tank, ready to go. All of that work would typically be done at the dealer.

If a dealer sold OMC engines--and that would have been common for a Boston Whaler dealer, particularly to sell Evinrude engines--then the dealer would bundle an OMC engine with the Boston Whaler boat, install the engine, rig the engine to remote controls, and to a fuel tank. So the dealer could be selling a particular fuel tank that matched the particular outboard brand he was selling.

There was no linkage between Boston Whaler and Mercury in c.1998. And Boston Whaler was not selling boats with engines installed.

At some point--I have not researched the exact year when this happened--Boston Whaler began to offer an option to order a boat to be pre-rigged for a certain brand of engine, which would make the installation of the engine at the dealer less complex.

There is a lot of information about metal fuel tanks that MIGHT have been available in c.1988. See this article in the REFERENCE section:

On-Deck Fuel Tanks
https://continuouswave.com/whaler/refer ... lTank.html

If the "metal" fuel tank you have that is a 12-gallon fuel tank is an ALUMINUM fuel tank, you could have a MIRAX fuel tank. Read the article linked above and you will find more information about MIRAX fuel tanks.

MIRAX is still making an aluminum 12-gallon fuel tank which is advertised as being sized for a Boston Whaler MONTAUK 17 boat. They have a nice website that shows their 12-gallon aluminum fuel tanks. The tanks have a big label on them that says "MIRAX." My presumption is that by saying the tanks are sized for a Boston Whaler means that a pair of these fuel tanks will fit under the reversible pilot seat of a Boston Whaler MONTAUK 17.

More information about MIRAX is on their website. Their website is linked in the REFERENCE article mentioned above. Here is the link:

MIRAX FUEL TANKS
https://miraxfuelproducts.com/

I understand that you cannot easily seen the fuel tanks that are on your boat, but maybe you can remember what the fuel tanks look like, and perhaps they look like they are MIRAX fuel tanks. In that case, your problem is solved.

Figure 2 below shows the fuel tanks I am asking about.

Q2: are your fuel tanks aluminum or steel?

[The fuel tanks which are the topic of this discussion are made from] aluminum.

I have found information about a new gasket.

I have not found information about a new fuel tank cap.

ASIDE: the engine is a 1989 Johnson 90-HP two-stroke-power-cycle model with automatic fuel-oil mixing.

Your aluminum fuel tanks have a strong resemblance to the the MIRAX fuel tanks I mentioned in an earlier post, particularly in regard to where the fuel tank level indicator gauge is located.