Gas tanks

[John2189 454]

I know you’re supposed to fill steel gas tanks up with gas that’s treated over the winter to keep it from rusting, but what about plastic tanks?

[ebinmaine 67,729]

I have both steel and plastic gas tanks in my fleet.

 

I never use any additives. Zero.

 

No ethanol. No additives. No problems.

[Pullstart 62,924]

You can also drain them completely.  No ethanol, no problems.

[WHX?? 48,845]

I keep them somewhat filled and a touch of seafoam. I suppose a touch of  heet as used in cars wouldn't hurt if you suspect moisture is going to be a problem. Although plastics aren't as prone to sweating the same procedure wouldn't hurt them. 

 

If for some reason you don't have access to corn free juice would the ethanol , which of course is alcohol, keep moisture at bay?

[ebinmaine 67,729]

22 minutes ago, WHX?? said:

I keep them somewhat filled and a touch of seafoam. I suppose a touch of  heet as used in cars wouldn't hurt if you suspect moisture is going to be a problem. Although plastics aren't as prone to sweating the same procedure wouldn't hurt them. 

 

If for some reason you don't have access to corn free juice would the ethanol , which of course is alcohol, keep moisture at bay?

 

 

Vehicle dry gas is either methanol or isopropyl alcohols. Ethanol is also attracted to water.

 

The problem with keeping any sort of alcohol in any sort of steel tank is that nearly zero of said steel tanks are designed to pull off the bottom of the tank like a lot of tractor tanks ALMOST do. There's that little layer of residue which will rust the bottom of the tank.

 

 

No alcohol should be in any tank. Period. 

[pacer 3,174]

I'm with Eric here .... I just leave them with non ethanol under cover and have never had a problem. One of the most remarkable events was with a hand tiller that I never used anymore, some 6-8yrs, and my neighbor wanted to use it. Pulled it out and I wanted to drain the old gas, neighbor sez, no, no no, it;ll be Ok -- so, go ahead ... dang thing started on 3rd pull!!!  I have a cyclone blower that gets used 3-4 times a year and has been running on the same gas for some 4-5 yrs now. This is really mostly because I just dont remember to ck the gas

[Lee1977 6,677]

1 hour ago, WHX?? said:

I keep them somewhat filled and a touch of seafoam. I suppose a touch of  heet as used in cars wouldn't hurt if you suspect moisture is going to be a problem. Although plastics aren't as prone to sweating the same procedure wouldn't hurt them. 

 

If for some reason you don't have access to corn free juice would the ethanol , which of course is alcohol, keep moisture at bay?

Ethanol draws morsture  and will cause a metal tank to rust.  The humidity around here is usually high.

[WHX?? 48,845]

2 hours ago, ebinmaine said:

Ethanol is also attracted to water.

Yes I forgot about that.

Back in the day Grampa used use to put grain alcohol in ice drill tanks for moisture in the day of finicky two strokes. That is if @Achto didn't empty the bottle ... 

 'Course he didn't mix gas and oil proper either just dumped in whatever he thought was right... and usually drain oil ... 

[953 nut 55,376]

      There are two correct ways to do it.   Drain the tank for storage or nearly fill it with non-ethanol gas with sta-bil gas additive. Just my opinion.

[adsm08 2,095]

11 hours ago, John2189 said:

I know you’re supposed to fill steel gas tanks up with gas that’s treated over the winter to keep it from rusting, but what about plastic tanks?

 

Plastic tanks tend to not rust.

 

I did see a plastic bumper cover that rusted once though. I think it was actually the metal flake in the paint.

[leabassett@sbcglobal.net 150]

13 hours ago, ebinmaine said:

 

 

Vehicle dry gas is either methanol or isopropyl alcohols. Ethanol is also attracted to water.

 

The problem with keeping any sort of alcohol in any sort of steel tank is that nearly zero of said steel tanks are designed to pull off the bottom of the tank like a lot of tractor tanks ALMOST do. There's that little layer of residue which will rust the bottom of the tank.

 

 

No alcohol should be in any tank. Period. 

Any tractor tank I have seen gets its gas from the bottom of the tank. I have never seen a tank with the fuel line coming off the side of a tank. Do you have any picks?

[wh500special 2,188]

Vented tanks - regardless of material - exhale when warm temperatures expand the air and vapors inside them then inhale when things cool down and the air contracts.  During the inward breath, ambient moisture from humidity is drawn back in with the air.   That moisture can condense or rain out when the temperature drops further and will become trapped within whatever fuel is left in the tank.  
 

Liquid fuel also expands and contracts with temperature fluctuations but to a lesser extent than the gas and vapor phases.   Keeping your tank full decreases the volume of air that can be exchanged during every breathing cycle.  

 

A fully empty tank has less opportunity to trap the moisture inside as the little bit of water that comes in is more available to vaporize. 
 

Keeping your tank all the way full or all the way empty is the best shot at keeping moisture accumulation at bay.  This is regardless of what special flavor of fuel you like to run. 
 

In a bare steel tank, keeping the tank full of fuel discourages rusting of the inside of the tank by excluding oxygen from the surface.  Plastic, of course, is free of this concern. 
 

The amount of water drawn inside the tank during each breathing cycle is quite minimal, but during prolonged storage time can work against you.  Most days will have at least one cycle.   Condensed moisture will enter the fuel via gravity and will either sink to the bottom of the tank (pure gasoline) or will be held in solution by the fuel (ethanol or stabilized fuels).  Give it long enough and you’ll eventually see the water in the bottom of the tank.  
 

This happens much sooner with pure gasoline than with alcohol laced fuels that can hold a lot of water that can be invisible one day as it’s safely held in suspension for but can drop out the next when the alcohol can hold no more.  
 

Another possible benefit to the completely full or completely empty approach is that you can optimize (minimize) the amount of surface area of fuel that makes contact with the surrounding air.  While it is slow to occur, some of the constituents of gasoline will react with oxygen in the air to create either undesirable products that can settle in the tank or just don’t burn well.   There’s also the evaporative loss of some of the lightweight things that are in gasoline that make it burn nicely and fire off a cold engine easily.  
 

Full or empty should provide the best options.  
 

Steve

[ebinmaine 67,729]

5 hours ago, leabassett@sbcglobal.net said:

Any tractor tank I have seen gets its gas from the bottom of the tank. I have never seen a tank with the fuel line coming off the side of a tank. Do you have any picks?

 

 

We have four types of fuel tanks on our current Herd of tractors. All drain from the bottom. 

 

1. Metal of various shapes. The outlet is a threaded fitting. This leaves a space at the bottom of the tank that can never fully drain. Residues and rust DO collect all over the bottom of the tank. 

 

2. 80s and up rear mounted. Plastic. 

 

3.  1974 to 1977 under the hood. Plastic. 

 

Both #2 and #3 have a push-in type metal fitting that uses a rubber (or other material) grommet as the seal. These leave an even larger amount of fuel in the bottom. Obviously being plastic the tanks aren't able to rust but the fitting does. Other residues still collect.  

 

4. Early 70s under the hood. Plastic. 

These have a nipple as part of the bottom of the tank. No shutoff. 

 

This is the ONLY type that has any capability of draining the entire tank if the machine is set so the nipple is at the lowest point. 

[Handy Don 12,265]

5 hours ago, ebinmaine said:

four types of fuel tanks

The cast aluminum round hood tanks can fully drain if set dead level. They don’t rust either! 

[953 nut 55,376]

9 hours ago, Handy Don said:

They don’t rust either! 

Wow, aluminum won't rust !!!!!!!!!!!!!!!     Just a guess but could that be because there is no iron (Fe) in it ????"?                            

[adsm08 2,095]

2 minutes ago, 953 nut said:

Wow, aluminum won't rust !!!!!!!!!!!!!!!     Just a guess but could that be because there is no iron (Fe) in it ????"?                            

 

It might not rust, but it sure does corrode just fine.

 

My service desk sure does get uppity when they ask me to look at rust spots on aluminum panels and I tell them I can't find any rust.

[leabassett@sbcglobal.net 150]

On 11/20/2024 at 4:33 AM, ebinmaine said:

 

 

We have four types of fuel tanks on our current Herd of tractors. All drain from the bottom. 

 

1. Metal of various shapes. The outlet is a threaded fitting. This leaves a space at the bottom of the tank that can never fully drain. Residues and rust DO collect all over the bottom of the tank. 

 

2. 80s and up rear mounted. Plastic. 

 

3.  1974 to 1977 under the hood. Plastic. 

 

Both #2 and #3 have a push-in type metal fitting that uses a rubber (or other material) grommet as the seal. These leave an even larger amount of fuel in the bottom. Obviously being plastic the tanks aren't able to rust but the fitting does. Other residues still collect.  

 

4. Early 70s under the hood. Plastic. 

These have a nipple as part of the bottom of the tank. No shutoff. 

 

This is the ONLY type that has any capability of draining the entire tank if the machine is set so the nipple is at the lowest point. 

I see what you are saying now. This makes it clear now.

[clueless 3,005]

High Density Polyethylene doesn't rust or break down, no need to store gas in them for the winter.

 

[pacer 3,174]

Agreed that Aluminum doesnt 'rust' but.... it does do ... something very similar ---- think of your spindles on the mower deck, they can 'rust' so badly that they cant be mounted. But, I agree that fuel is not gonna cause this....