metal vs plastic fuel tank...which is better?

Need some guidance from the guys who know. I am buying a 1974 20 hp mercury that I need to get a 6 gallon tank for. I found a company that still makes the metal 6 gallon tank for $59.00. The plasctic one is the same price. I have read that the plastic ones swell up. Is there a reason not to go with a brand new metal tank over a new plastic tank? This tank will sit on the floor of my 14 ft smoker craft and will not be stored outside when not in use. Thanks for your help.

You found a company that makes metal tanks for 59 bucks? Please pass along the name and website of this company! Plastic tanks do swell when its hot outside, but I have never seen it get dangerous. They each have their positives and negatives, but if I could find a brand new 6 gal tank for 60 bucks I would do that in a heart beat. Might be a good idea to coat the inside with some sort of solvent proof paint designed for gas tanks to prevent future rusting.
Chris

Chris,

let me order mine (they had 480 in stock) and I will pass the website along to you.

Tim

Here is the website:

https://greatlakesskipper.com/product/37_452_623-boat-engines-engine-parts-and-accessories-fuel-tanks-aluminum/7134--custom-6-gallon-steel-vented-marine-boat-gas-tank-w-fuel-gauge.html

buy a plastic one and not have to worry about crap clogging up your fuel lines down the road. and when it gets real hot unscrew the cap every once in a while if it makes ya feel better.

shawnfish said:

buy a plastic one and not have to worry about crap clogging up your fuel lines down the road. and when it gets real hot unscrew the cap every once in a while if it makes ya feel better.

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With you on that With tat crappy gas /alc/water mix we get Corrosion in metal tanks is bad...Once you find the sweet spot on vent plastic tanks stabalize...cva34

I contend that a metal tank that has been coated with some sort of gas tank liner will out last a plastic tank that expands and contracts with heat, I would assume this over time would stretch and somewhat weaken the plastic. Plus plastic is not nearly as strong as steel and something heavy being dropped on the plastic tank could potentially puncture a hole or rip a gash in it. Steel would eliminate this possibility. I agree that with steel the potential for rust is present, which could cause engine troubles, but with a good coating of tank sealer this should be eliminated.
Not trying to argue with anyone, I just hate how everything is made of plastic these days. Something are ok and even improved when made of plastic, but a fuel tank should be tough enough to withstand shocks and plastic just isn't the best thing for that.
Chris

shawnfish said:

buy a plastic one and not have to worry about crap clogging up your fuel lines down the road. and when it gets real hot unscrew the cap every once in a while if it makes ya feel better.

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Fuel left in any tank, of any material, will produce residue which can go through a fuel line.
However...........the plastic tanks readily expand with heat. This expansion will continually break loose what is stuck to the sides of the tank and allow it to run through the fuel system alot easier than a metal tank will. Plastic tanks leak alot easier than a metal tank will.
Plastic tanks look like a football when hot and can move around inside the boat very easily when they become round from expansion...... No footballs for me!

What do you recommend product wise to use to coat the inside of a new metal tank? I have pretty much decided to go with the metal tank. The shop that I am buying the motor from said to get a metal tank if at all possible. My Grandpa (rest his soul) use a metal tank with is 9 hp Montgomery Ward and if it was good enough for him, it is good enough for me.

I wouldn't coat it with anything

Going to be trash in your fuel nomatter what type of tank you have. Fuel filters are cheap

Hadn't really thought about an inline fuel filter but I would do both the filter and the coating. The coating is more for future corrosion issues that may arise. Personally I have never used any of the tank coatings so I can't recommend one, but others on here that have experience have mentioned Kreme and products made sold by Eastwood. From what I have seen the Kreme are the most cost efficient, which doesn't always translate to the best but with the lower price you could do it every couple of years if ya felt it was necessary.
Chris

Kreme, POR-15, and other liner kits like them were not developed for new tanks. They were designed to give useful life back to tanks that were impossible to replace (no longer mfg'd) and had developed a rust problem. The liners resemble a coat of fuel resistant thick paint that is poured into the tank after prep work and sloshed around until all surfaces are coated. The excess is drained and the remainder allowed to harden several days. Kreme has a reputation for peeling, but I suspect that is most often due to poor or improper prep work. I used POR-15 on my motorcycle gas tank 5 years ago and it's still holding up fine. But I never would have put that stuff in my tank if it didn't have a rust issue. If I could have replaced the tank with a new one I would have gone that route rather than deal with a liner kit. Besides all of that, the cost of a liner kit is almost as much as a new outboard tank so why mess with it. It's my understanding that metal tanks have some sort of rust inhibitor coating when made and rust only develops as a result of water getting into them and staying there for prolonged periods.

Running these fuels with ethanol may present more of a challenge to keep water out of the tank and preventing rust because of the way ethanol sucks up moisture. But I'd personally prefer to have a metal tank and hope I can find one when it's time to replace my current tank.

A metal tank needs absolutely nothing as far as coatings. Remember.....if you leave old fuel in a tank, coated or not, it will leave a residue. Common sense cleaning of the outside and underside of the tank and keeping your fuel fresh are the only keys to longevity of the tank.

I have both. I haven't had a problem with fuel residue on either. The inside is nice and clean. The only problem I'm experiencing now is the paint is failing on the metal can, and I'm getting paint flakes inside. It could be due to neglect of the previous owner, or maybe a poor paint job?

edit: Any ideas how I should clean this up? I'm thinking strip it down completely?

I have used both metal and plastic tanks. Just common sense care kept both working right. I now have 2 quality plastic omc tanks, 6 gal each, they work just fine and are tough. They do expand, so what, it is not an issue. The inside of my metal tank did not have paint or anything on it and I used it 25 years. Use the leftover gas in your snowblower every season or use in your car, then coat the metal tank inside with some 2 cycle oil to keep it from rusting. Your set to go next spring.
Tim

Either tank is fine. Neither is a clear cut winner over the other.

jasper60103 said:

I have both. I haven't had a problem with fuel residue on either. The inside is nice and clean. The only problem I'm experiencing now is the paint is failing on the metal can, and I'm getting paint flakes inside. It could be due to neglect of the previous owner, or maybe a poor paint job?

edit: Any ideas how I should clean this up? I'm thinking strip it down completely?

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Looks like factory paint on an older tank. It could be flaking off due to age, wear, or the ethanol additives we're being forced to use today. I'd try to strip the rest of the loose paint, clean, prime, and repaint it. You'll need to find a gas/oil resistant paint if you expect the new paint job to last long though. And always keep a clean dry rag handy when you fill it to wipe off an spills. Even fuel resistant paint will break down when soaked in gas for prolonged periods.

My metal tanks are 24 y/o and perfectly fine on the bottom and inside.

If you do go with a coat the kreme liner works great, but you can also buy a new tank for as much as the kit costs

I had no idea metal tanks were still available. Thanks for that link. For that price I am ordering 2!!!!! I hate plastic gas tanks, especially the after market ones. The one that came with my 20hp Merc fourstroke seems to be of good quality but the rest I have just suck. Cheap plastic fittings etc.

Mike,
thanks for the tip. I agree, the tank is an oldie and the original paint is just showing signs of age. I decided I really don't want to work with harsh chemicals, so I will see if some light sanding will take off the rest of the paint, especially around the spout. Else, I will just get a new metal tank eventually. Thanks again.