Clean or replace alum fuel tank?

[superbenk]

My 30 yr old boat started sputtering & I have a feeling it's picking up varnish from a poorly maintained fuel tank. The tank is a 12-15 gallon aluminum rectangular tank & I'm wondering if it's best (cheapest) to pursue cleaning it or just replacing it with a new plastic tank (pending confirming it's actually got varnish in it)? The tank sits on top of the stringers in the bow of the boat, so it *shouldn't* be hard to remove/replace. I'll need to hook up a filler tube, vent tube & pickup line.

If replacing it is recommended, what type of tank should I look at? Will this orange above-deck tank work:


or should I look at one of these below deck tanks:


Is there an advantage of aluminum I'd be losing if I switched to plastic or are plastic tanks better long-term?

 

[Bondo]

Re: Clean or replace alum fuel tank?

Is there an advantage of aluminum I'd be losing if I switched to plastic or are plastic tanks better long-term?

Ayuh,... This is probably the Wrong forum, as it has really Nothing to do with a motor or drive,...
But,...
Plastic is the Only way to go....
Aluminum Corrodes...

 

[superbenk]

Re: Clean or replace alum fuel tank?

Ayuh,... This is probably the Wrong forum, as it has really Nothing to do with a motor or drive,...

Ah, you're right. I don't know how (if I can) to move it.

Also, I did a measurement on the outside dimensions of my tank and it turns out it's a lot bigger than I expected (~25 gallons, not 12-15).

 

[Big Keepers]

Re: Clean or replace alum fuel tank?

My 1979 MFG has a 44 gallon aluminum tank. Surprisingly the inside was very clean when I took it out of my boat to look it over. If Pennsylvania has ethanol blended gasoline, which it should, also known as E-10 gas, the ethanol will clean the inside of that tank for you. Its a solvent. You need a quality fuel filter installed in line like a Racor. Run a couple of full tanks of gas through that filter and the tank should be emptied of any varnish that was on the walls. Then change that filter. Hopefully you haven't tarnished your carburetors already. I was lucky enough to be able to get rid of bad gas in large quantities so I put about 10 or so gallons in my tank and left it in the bed of my pickup for a few days to slosh around. Then I siphoned it out and started from there. I still installed a Racor filter with the sight glass bowl on the bottom to see what kind of gas is coming out of my tank.

 

[dingbat]

Re: Clean or replace alum fuel tank?

While plastic may in theory may be the way to go, who here has a 30 year old plastic tank that can vouch for it's longevity?

Lots of 30 year old aluminum tanks still in use today.

 

[superbenk]

Re: Clean or replace alum fuel tank?

While plastic may in theory may be the way to go, who here has a 30 year old plastic tank that can vouch for it's longevity?

Lots of 30 year old aluminum tanks still in use today.

If we do opt to keep the aluminum tank & it does need cleaning, what can I expect it to cost? Is this something I should try to do myself or hire it out? A friend of mine that did it himself said he ended up cutting the tank open & cleaning & then welding it back together again. I don't have any knowledge or tools to weld aluminum, so that's not really an option if that's what is required.

 

[dingbat]

Re: Clean or replace alum fuel tank?

If we do opt to keep the aluminum tank & it does need cleaning, what can I expect it to cost? Is this something I should try to do myself or hire it out? A friend of mine that did it himself said he ended up cutting the tank open & cleaning & then welding it back together again. I don't have any knowledge or tools to weld aluminum, so that's not really an option if that's what is required.

As noted in the post above you really shouldn't have to do anything to the inside of the tank. E-10 fuels will do the work for you.

Problem is, if you don't have a 10 micron filter/ separator in place, all the dislodged gunk from the tank and the bits of pieces of rubber that flake off from the inside of the hoses go directly into the carbs and plug them up.

When burning E-10 fuel a 10 micron filter/ separator is mandatory. Install a 10micron filter assembly and while your at it, change out all the fuel lines on the boat if you have not already done it.

Once you get things in order you'll need to tear down the carbs down and clean them out. Should be good to go after that.