Plastic gas tanks

Darryl G said:

Probably just water from condensation. Is the mower stored in an area where the temperature fluctuates significantly?

Click to expand...

Yes. I wish I had a better place to store it. I DO keep an ATV cover on it at all times but that's no protection from the high temperature fluctuations. I think keeping the gas tanks full will help to some degree with allowing humid air from being sucked into the tanks when they have a large air space.

Seafoam is what I like best. But everyone has their own preference.

ILENGINE said:

I have never seen the inside of the plastic tanks deteriorate like that, crack and get brittle yes but no leach. I suspect that you are picking up a mixture of ethanol, water, and the resulting bacteria that grows in that alcohol, dirt, water mixture. It can have the appearance of snot. The other think could be that the aluminum carb is corroding and you are getting aluminum oxide which is a white powdery substance that can look like a grey/white sludge.

Click to expand...

Ilengine; I don't know for sure that the inside of my tanks are breaking down. Just a possibility that occurred to me. Since the mower is an '07, I thought that age may be wreaking havoc on the plastic. I don't know if there is a special coating on the inside or not. I DO know that fuel vapors do leach through plastic tanks over time. My tanks have discolored severely over time from being the light gray color to a much darker gray/brown color that is worse at the bottom and gets gradually lighter gray as it gets closer to the top. At 12 years old, I suppose this is a normal result. Just the way it is and I'll jet have to continue working with it and try to minimize it by keeping the tanks full.

7394 said:

Seafoam is what I like best. But everyone has their own preference.

Click to expand...

Sea Foam is in my arsenal as well. I just checked my inventory and I have 11 cans left. Time to hit Wallyworld.

Tanks are made from HDPE ( High Density Polly Ethylene ) it is the only material that they are allowed to be made from for quite some time.
Like all plastics, HDPE is not fully stabe.
Like every material on the planet HDPE is not immune to the effect of UV rays.
Sunlight will eventually cause the plasticizers to oxadize and the tank will become brittle and start to go chalky on the outside.
On the inside they should be stable till the UV damage penetrates full depth.

I suspect what you are seeing is "Phase separation".
This happens because ethanol is not soluable in petrol and much like the old days of mixing engine oil with petrol to make 2 stroke fuel, eventually the ethanol separates out.
Ethanol also adsorbs water and when it does this it becomes heavier than the petrol so it sinks to the bottom of the tank.
The final stage is a bacterial growth in the water / ethanol mix and the dead bodies & excertia from the bacteria makes a jelly like substance.

It is very similar to the fungus that grows in diesel and the alge that grows in Jet A1

Boit4852 said:

Yes. I wish I had a better place to store it. I DO keep an ATV cover on it at all times but that's no protection from the high temperature fluctuations. I think keeping the gas tanks full will help to some degree with allowing humid air from being sucked into the tanks when they have a large air space.

Click to expand...

Yes, it should help both to minimize internal condensation and to preserve the gas better during storage by reducing volatilization of the volatile components of the gas.

Edit:. BTW one of my machines is the same as yours, a 2003 Lazer Z HP. It's stored in an unheated shed and I've never had issues with water in the fuel storing it with the tanks filled to nearly the bottom of the filler neck. And that's with E10 gasoline.

I have an ‘04
No issues with the tank material breaking down. No water issues, I do use sea foam

If you have water issues in fuel, you are getting it from the gas station.

Change the brand of gas you are using.

100% real gas is best.