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Q1: on the original Florida Marine Tank fuel tank used in an 1986 OUTRAGE 18, what is the tag number?

BACKSTORY
I want to install a new fuel tank in my 1986 Outrage 18. I prefer to use the OEM supplier, Florida Marine Tank (which now located in North Carolina).

When I contacted FMT, the representative asked if I had the “tag number” on the tank. I do not, since the original tank in my boat was replaced by a non OEM tank some years ago.

Q2: what is the volume capacity of the OEM fuel tank in a c.1986 OUTRAGE 18?

Also, I anticipate that the "tag number" refers to the field on the fuel tank label that is denoted as "Tank Model Number." Compare below with a random label from an FMT tank.

Here is the original drawing from FMT for the tank.

[I have deleted the attached file for the following reasons: it showed a 77-gallon fuel tank; the file name suggested this drawing was appropriate for an 18-foot hull, but later it was determined that was in error. Rather than let this mis-named file stick around and confuse everyone, I have deleted the file. I will also upload the file, with a proper file name, to the REFERENCE article on On-line Drawings and indicate this drawing is for the 22-foot hull fuel tank. So many thanks to PHIL T for uploading the file, which is now in a more appropriate location on the website--jimh]

Phil, I do not think that is the correct drawing, because it is for a 77 gallon tank. The OE tank on the Outrage 18 was 63 gallons.

A 63-gallon fuel tank is what the specifications show in the REFERENCE section article. Compare at

1981- 1990 Outrage 18
1991 Outrage 19
1992 Outrage 19 II
https://continuouswave.com/whaler/reference/18Outrage/

If you read the reference article, there is a hyperlinked text that leads to the drawing for the 63-gallon fuel tank in the section under the sub-heading “Fuel Tank.”

Below is the URL to the drawing for the FMT fuel tank that was used in the c.1986 OUTRAGE 18. This drawing should be useful to help FMT locate their original drawing:

https://continuouswave.com/whaler/refer ... elTank.pdf

IMPORTANT
Note that the 63-gallon FMT fuel tank cross-section is asymmetrical.

Thanks for the correction.

My attached drawing is the tank for the Outrage/Revenge 22.

Mea Culpa.

It has been a few years since a report about the cost of replacement fuel tanks from FMT has been cited. To get a quote from them to see the current price would be informative.

Another option might be to resort to an on-deck fuel tank (or two). Twin 22-gallon tanks would give 44-gallons or more than two-thirds of the original capacity. Coupled with a modern outboard engine with much improved fuel economy compared to a 1980s two-stroke-power-cycle carburetor engine, the useful range would remain the same. Fuel management with two separate tanks could allow the boat to be operated on shorter endurance trips with less fuel aboard, maybe just carrying one on-deck tank.

Total boat weight would be reduced, so performance might improve. With translucent plastic tanks you can visually see the fuel level, so there is no ambiguity about how much fuel remains.

The vacant space of the fuel tank cavity could be re-fitted with a large access hatch in the deck and used for storing gear.

It might be worth a try. If actual use with on-deck tanks turns out to be too awkward, you can always order a replacement below deck tank.

The suitability of less fuel capacity really depends on how the boat would be used.

The preliminary quote for a replacement tank from FMT is $1,440, and shipping costs are at additional charge.

Notably, the quote also includes this proviso: "We no longer stock or purchase Wema or Rochester Twin-Site senders (visual gauges)."

Since I would like to return the boat to original, and I think the Rochester mechanical fuel gauge may still be available from the manufacturer. I am going to pursue that idea to see if I can add that to the new tank.

I am going from memory, and as I recall the OEM tank has an unusual four-bolt mounting flange for the Rochester gauge. I believe that a more common flange for attaching a float level style gauge uses a five-bolt mounting flange. If you can’t work out the arrangements to send FMT the Rochester gauge to install, you might give some thought to changing to the more common (at least I thinks it is more common) five-bolt arrangement, the using a more modern tank level sender like a WEMA (now SSL) electrical cylindrical type.

A bit more follow-up about fuel tank drawings:

63-gallon Fuel Tank Drawing
The drawing for the fuel tank for the 18-foot hull (which is linked in my earlier reply) is also listed in the REFERENCE section article on drawings of components for Boston Whaler boats which are available for download, sorted by hull length. The URL for that list is

Drawings of Boston Whaler Components Available Online
https://continuouswave.com/whaler/refer ... wings.html

There is one element of the 18-footer CAD drawing that seems to be at odds with the actual fuel tanks from FMT in the classic era. The CAD drawing notes that the tank finish is to be "gray paint." In my own experience, the c.1990 FMT fuel tank on boat my has a green paint finish, which one often sees on aluminum (such as used in aircraft) and is an anti-corrosion paint finish; typically a zinc-phosphate paint would be used. Compare at:

A-702 Valspar Primer Green
https://www.aircraftspruce.com/catalog/ ... -02127.php

Also, I do not know with certainty if this CAD-style drawing originated with FMT or not. The drawing uses colors to separate drawing elements, which is different from another CAD-style drawing that is believed to be from FMT which is a monochrome (black/white) drawing.

77-gallon Fuel Tank Drawing
In an earlier post a drawing for a 77-gallon fuel tank was uploaded to this thread and mentioned as appropriate for an OUTRAGE 18. In the course of the discussion that was discovered to be in error, as the 77-gallon fuel tank was more appropriate for the 22-foot hull. To eliminate confusion, I have removed that drawing from this thread.

However, I noticed that there was no drawing for a 77-gallon fuel tank listed in the REFERENCE section article on drawings available. Accordingly, I have preserved the drawing for the 77-gallon FMT tank, but I have changed the file name to avoid confusion (as the original file name mentioned the 18-foot hull, not the 22-foot hull). I have uploaded the renamed file to the REFERENCE section. Further I have revised the article that lists drawings available for download to include a mention of the file, noting it as the 22-foot hull fuel tank. Here is a direct link to the 77-gallon (22-foot hull) fuel tank drawing:

https://continuouswave.com/whaler/refer ... elTank.pdf

That 22-foot fuel tank drawing also appears to have been drawn using some computer-aided design (CAD) graphic program, but it looks much more like an authentic FMT drawing as it includes some notations in pencil in the PDF file. The 77-gallon drawing also includes a long list of revision, beginning on 6-30-1987 and ending on 10-11-2006.

Among the revision is a note related to the fuel tank level gauge. Here is that excerpted text:

10-7-93 DROP GAUGE TWR 4 HOLE VIS. 8 3/8 X 6 1/8, CHNG FLOAT FR/ FACING AFT
CHANG FR/ ZINC SCREENS.

The mention of "4 HOLE" seems to confirm my recollection that the bolt circle for the Rochester tank level gauge may have been a 4-hole bolt circle. The updated drawing shows a 5-hole bolt circle, which sounds more appropriate for other types of fuel tank level indicator devices.

grizzly wrote:The preliminary quote for a replacement tank from FMT is $1440, and shipping costs are at additional charge.

Thanks for the information on a current cost for a replacement from the OEM, Florida Marine Tanks. The cost is not as high as I was anticipating. Given how the cost of almost anything manufactured has risen about 50-percent in the years 2020 to 2024, the custom fabricated aluminum welded fuel tanks seems to still be affordable.

Please keep the forum advised on your plans and purchases regarding this project.

In the above discussion I mentioned a WEMA fuel tank level gauge. The WEMA brand has been taken over by SSL.

I have NOT used one of these senders myself, but they look interesting. The "float" mechanism slides on a vertical pipe. For more about the SSL ( nee WEMA) and other options for electrical fuel tank level gauges see an earlier discussion on that topic at

Fuel Tank Level Sender: Electrical
https://continuouswave.com/forum/viewtopic.php?t=3095

If you choose an electrical-based tank level sender, you will need an appropriate fuel tank gauge that works with the particular resistance range used in the sender.

There are also more exotic tank level senders which employ a SONAR-type mechanism to sense the depth of the liquid in the tank, but that approach seems too complicated for a simple outboard engine 18-footer.