1979 170 fuel tank replacement

[seabob4]

That's why I foamed mine in, epoxy coated, and waterproofed. I also use solid cover plates. No way for water to get in.

Kraw, while solid pies eliminate a potential leak point at the seal for the center cap, they can make yearly fuel system inspections problematic.  ABYC recommends them, as do I.  Most owners, when they pull off the solid pie to inspect there hose clamps, hoses, and wiring, will fail to re-bed the pies upon reinstallation.  Good concientious owners will do it right, but there aren't a whole lot of those types floating around out there.  The twist out or pry out solves that issue...

[alandry100]

Just got a quote for $340 +shipping from speedy, this is a lot higher than the $9 a gallon I have heard as an estimate. Has the price of aluminum gone up?

[kraw2]

That sound right to me. It's at least $10 a gallon around here.

[gran398]

It's a free call. Plus an additional 10% off to CAS members.

Will be interested to see how they compare to your quote.

viewtopic.php?f=12&t=9353

[Mack]

Don't know if you have found a tank yet, but if you need a source you can contact "Florida Marine Tanks"
FMT manufactured tanks for Aquasport for many years and still has the original drawings dating back to early 70's.
FMT moved to North Carolina, and you can locate them on the internet.
Improvements to the original design include: Fuel pick-up tube moved from center to rear of tank; Fuel fill tube and vent tube moved to from center to front of tank; Electric sending unit now standard replacing visual gauge.

I would definately consider keeping a drain hole at the rear of the fuel tank compartment.  You don't want to take the chance that a fuel leak would allow that compartment to flood with fuel.
Also I would think foaming in the tank would not be advisable because in the event of a fuel leak the foam could become saturated with fuel and pose a safety issue.  

I changed the tank on my Aquasport 17' couple of years ago and bought my tank from FMT.
I laminated 1/4" neoprene strips to the bottom of the tank compartment, length-wise as SeaBob4 suggested, so that moisture will drain out of the compartment .
I ran a bead of silicone caulk around the perimeter of the underside of the compartment hatch cover, and allowed it to dry before installing the hatch cover over the compartment. I then caulked the cover with 4200 to help prevent water from entering the compartment.

[Coverhill]

I'm the long time owner of a 17' Osprey that was manufactured in 1988.
My boat has always been located in south Florida and used only in salt water.

In 1999 I decided that my aluminum fuel tank had deteriorated sufficiently
that I should replace it was a new aluminum tank. My original factory
installed tank when removed looked very similar in condition to the photos
shown in this thread of other tanks being removed from Aquasports. Not
a pretty sight, and only after a dozen years.

I chose to have a local fabricator who worked in aluminum make me a new
custom made tank, after I vistited their shop and saw that they were were in
fact fully skilled to do the job; they had several boating projects in process
at the time of my visit. They built me a new tank from 1/8" thick "5086"
aluminum. "5086" is an aluminum alloy specifically for marine applications
such as building hulls of aluminum. It is corrosion resistant and I'm adding
here a photo of what my "5086" tank looks like 13 years after I installed it
in my Aquasport (see photo showing fuel gage through clear plastic "pie
plate" - NO corrosion of the aluminum). Any one having a tank made should
ask about having it done in "5086"; it will cost more but will last much longer.
Suggest you "Wikipaedia" the words "Aluminum Alloy" and then go down
and click on "5086" and read about this specific alloy.

The main point of this post is to advise that I was able to increase the fuel
capacity of my tank from the factory 27 gallons to a new 35 gallon capacity.
This was accomplished by my measuring the tank well of the boat and then
having the new tank made to fill that space completely but with ample room
to get the tank in place (and remove it later if necessary). The new tank's
end-on view is keystone shaped (20" at bottom and 22" at top) rather than
the original tank's 20" dimension for both top and bottom, and is 1" taller
than the original tank.

I do take very good care of my boat, wash it after every use, and store it
inside. I've just finished reworking it and it currently looks like a new boat. The
rework included putting on a 2011 year model 90hp Evinrude E-tec motor which
is a fuel injected 2-stroke engine. I've now tested that motor, using new GPS
electronics (Garmin 740S) to calculate speed and have updated my "Specs Card"
to include the new E-tec. I'm posting a photo of that card here as others might
want to do something similar. The "Card" was made on my computer's word
processor and then taken to a "Kinkos", now "FedX" store and there "plasticized"
(encapsulated in a plastic sleeve) that makes it durable and waterproof (costs
$two bucks). I got the floor fuel gage readings for my 35 gallon tank on the
first fuel fill after the tank was fabricated and completely empty to start.

My new electronics include (1) Evinrude's "I-Command" digital multifunction gage,
(made by Lowrence) , which shows actual fuel burn to the tenth of a gallon per hour
at every engine RPM, and (2) a Garmin 740S Charplotter which gives GPS speed and
which can also "import" all of the information produced by the "I-Command" system.
Between these two pieces of electronics there is NOTHING that you don't know
when you're running your boat: RPM, Speed, Fuel Burn, Miles per Gallon, Engine
Temp, Battery Voltage, Water Depth, Water Temp, etc.

NorthPalmBeach, FL

[alandry100]

After a few years of running the boat with a remote tank - Striper season came and I had to button it up - I am now back at it.





I am currently trying to get the fuel line and vent free. It is moving a bit but still not free - I am going to get at at it for a few more hours. If I can't get it out I will cut a pie hole on the deck but want to avoid it.

[alandry100]

Ok so several hours later - lots of foam removed - and lots of cursing - I freed up the vent and fill.



40 years have taken a toll





I was not able to chase them with new lines - not even sure how you would do that given the difficulty of getting the fill out. It was stiff as a board - hopefully the new line is a bit more flexible.



Now to get new lines - if anyone can recommend where to buy and exactly what kind of lines and what kind of fuel gauge to get that would be appreciated.

Got a quote for tank from Phil at Alloy Works and will be ordering this week.

[alandry100]

Longtime coming update - Just received a tank from Phil at Alloy, looks great. Got it in - hope I wired it up right.

[boatnamesue]

Looks good!!  What's your plan to secure the tank in the coffin?

[alandry100]

Oh yeah, I used the pascoe method. Thought I snapped pictures before I put it in, but no. Hopefully it sticks.

[alandry100]

So it seems like everything is good - but the fuel gauge always registers a level, even when the key is off. Is that ok or is it running down the battery?

[boatnamesue]

So it seems like everything is good - but the fuel gauge always registers a level, even when the key is off. Is that ok or is it running down the battery?

When the key is off the sender is not supplied with power, so no.  But if you haven't already sealed the fuel hatch I'd fix the sender so it reads accurately. 

[Capt. Bob]

Does the gauge move when you turn on the key? If so.....

Turn on the key, then turn it off. Try tapping on the gauge face. Did it move?

That's a brand new reed type sending unit and there is no adjustment on it as far as I know. Recheck your connections coming to the gauge itself. Of course you could remove the sender and slide the ring up and down to check the gauge.

Good luck.

[alandry100]

The gauge seems to work fine- full when full- goes down as I use gas. It looks like it is always on though.