Green Crystals in Fuel Filter

[rgranger]

Boiling point of Gasoline is ...

No. The ethanol evaporates first (check the boiling points of ethanol and gas [final boiling point ~ 400F]--big difference). I have run many gas evaporation tests.

It really is NOT gum or tepentine in modern fuels. It is corrosion from water absorption, and no, drying is NOT required. The water makes the ions mobile withing the fuel. A good anticorrosion additive will stop this. Keeping the fuel dry by closing the the portable tank vent also works well. Protect the tank so that the vent is safe from spray and rain.

I'm pretty sure, having participated in ASTM standards and test development for additives.

You are not wrong but that is an incomplete picture. Gasoline is a blend of many different hydrocarbons and the lighter ones evaporate first. Those smaller molecules have a boiling point of approximately 90F. The heavier ones have a higher boiling point. Ethanol's boiling point also varies with purity and as the concentration of water in the ethanol increases, the boiling point also increases. For example 100% pure ethanol boils at ~ 79F but by the time it is 80%/20% ethanol/water the temp is 173F. By the time the ethanol/water ration hits 50%:50% the boiling point reaches 198F. Unless your fuel is very dry, you are going to increase the ratio of ethanol in the carb's bowl as the fuel evaporates. Since I started running my engines dry after each use, I have not seen any corrosion in my carbs. It has been at least 10 years now. I even run E10 in my larger Yamaha 115 2-stroke (I know blasphamy) {I do add a little stabil} but I never leave any fuel in the engine when I am done. I run it dry every time. I could not afford to use the boat if I had to pay $6.75 a gallon for that beast. Now for my sailboat's kicker (a Tohatsu 6) I used ethanol-free but I rarely burned more than 6 gallons a season in my sailboat.

 

[Tally Ho]

The E10 fuel I use in my lawn edger plugs up the carburetor jets every year.

This requires me taking the float and carb off, cleaning the jets and reinstalling…fires up first pull that.

But the gunk in the carb is WHITE, not green. And nowhere near as voluminous as these photos.

Hard for me to believe that those green crystals are just from old gasoline.

Greg

 

[Davidasailor26]

The E10 fuel I use in my lawn edger plugs up the carburetor jets every year.

This requires me taking the float and carb off, cleaning the jets and reinstalling…fires up first pull that.

But the gunk in the carb is WHITE, not green. And nowhere near as voluminous as these photos.

Hard for me to believe that those green crystals are just from old gasoline.

Greg

I’ve had similar experiences until I started using SeaFoam. Since then I haven’t had to disassemble any carbs, whether in my edger, mower, leaf blower, or outboard. Until then each one needed an annual cleaning. In my case the gunk was always black bits, so still completely different from what the OP sees.

 

[Tally Ho]

I’ve had similar experiences until I started using SeaFoam. Since then I haven’t had to disassemble any carbs, whether in my edger, mower, leaf blower, or outboard. Until then each one needed an annual cleaning. In my case the gunk was always black bits, so still completely different from what the OP sees.

I put some Sta-bil in the tank last year, but still had gunk in the carb this spring.
The good news is that I am getting good at cleaning the carb.

Greg

 

[kloudie1]

We are fortunate that we can get ethanol free gasoline here. I normally have 15 gallons stored; it has SeaFoam and StaBil in it . It normally will last a couple of years in the sealed cans or until I have to run the generator for a bit after a hurricane. I bleed it off to the lawn mowers etc .. No more problems with gunk in the itty bitty carbs. I have never seen those kinds of "crystals" in gasoline.. In the huge storage tanks in the refinery, we've found things like blue jeans, hard hats, air hoses, scaffolding, but no green stuff.

 

[DArcy]

blue jeans

?!? What were people doing in there?
The crystals are a great mystery, I'm following this thread with great fascination. Maybe someone read this page and decided crystals would improve mileage:

Crystals Give Cars Better Gas Mileage — Peaceful Island

In September of 2020 where incredible gas mileage came from using Car Crystals on the dashboard of the test car The following story describes the remarkable results that happened in this full-sized American car driving across the country using only a fraction of the fuel. Click to Read…

www.peaceful-island.com

 

[jssailem]

crystals would improve mileage:

Only of value if it works on a boat.

 

[thinwater]

And I've used Biobor EB for 15 years and never had to work on a carb. Never drained one. It stops the corrosion, much simpler than all the faffing around with draining and dissembling. I'm just trying to make your life simpler.

Yesterday I went sailing. 8-year old motor, never been drained, started on the first pull. SImple. I got it for a song because the carb plugged up on the first owner withing a year. I cleaned it (idle jet was the problem) and have not been in it since. The corrosion has been stopped.

 

[RoyS]

The way I see it, thinking as a detective, there are only two possibilities. One, someone sabotaged your fuel tank, or two, you accidentally filled your fuel tank with something other than fuel. I am not a chemist but I doubt there is any gasoline in those fuel lines; it must be something else.

 

[DArcy]

I think it would be worth taking some of the crystals to a lab to get analyzed just to satisfy our curiosity. This is one of the stranger things I've seen on a boat.

 

[JamesG161]

It was not sugar, It did not dissolve in hot water.

Not a good test.
why not?

Put a Lollipop in hot water, it will not dissolve fast.

If you still have the crystal, put some in a closed glass jar for several days.

Pictures of start and end of that test would be nice.
_____
Tip on preventing future growth.
ALL crystals must be completely removed from your tank through to the carburetor.

One tiny crystal left, will promote more crystal growth.
Jim..

 

[thinwater]

... One tiny crystal left, will promote more crystal growth.
Jim..

Growth of what? Other than sugar, no supportable theory has been presented. Not that I do not support a very good cleaning. It only takes one crystal to clog something. The only thing I have ever seen build crystals in gas or diesel is a sever overdose of a poorly formulated additive, and nothing like that volume and not with that crystal structure. But that is one more theory; the OP grossly overdosed with some unknown additive with marginal gasoline solubility (I know of several diesel additives that will crystalize if not well mixed in with the fuel), thinking he could solve some problem. But I've tested many additives and never seen anything that looked just like that.

I think we all remain very curious.

---

But this is also an important point. Do not just pour an aditive into the tank. Put in a jerry can before filling the can, or add to the can and then swirl the can. There are a few, without naming names (none mention in this thread), that will sink right to the bottom and stay there. I always add additive either to the can before filling, or while filling if an installed tank. Add ONLY the recommended amount. More is NOT better and will not clean a carb that is clogged with corrosion products. Not happening.

I've heard several mentions of Stabil. It must be the blue/green Stabil Marine 360, not the red stuff. They are not the same and they are not interchangable (I have lab tested both side-by-side).

 

[Rick Webb]

That grey fuel line has a liner that appears to be completely gone.
Don't use that stuff usually found at WalMart or WM. Go to a decent auto parts place and buy the black rubber fuel line. It may take a couple of stops to find but get the Coast Guard approved fuel line, its printed on the hose.
I think those crystals are the liner that has broken down.

 

[mikeracca]

That grey fuel line has a liner that appears to be completely gone.
Don't use that stuff usually found at WalMart or WM. Go to a decent auto parts place and buy the black rubber fuel line. It may take a couple of stops to find but get the Coast Guard approved fuel line, its printed on the hose.
I think those crystals are the liner that has broken down.

This is what I was talking about from the Seadoos I have worked on. I have never seen it as a crystal, but a green gooey sludge that was once a fuel line. I imagine it could crystallize once dried, but I more figured it would just form a thin nasty film when dry. Honestly I never kept any of those lines around to find out what happens, they go into the garbage and the carbs get cleaned.

 

[SailingLoto]

Replace your fuel lines. It's the liner. I see it in green and tan. Ethanol exacerbates the problem.

 

[DArcy]

Replace your fuel lines. It's the liner. I see it in green and tan. Ethanol exacerbates the problem.

This makes the most sense, not very mysterious, but makes sense

 

[SailingLoto]

This makes the most sense, not very mysterious, but makes sense

Yeah, I find it in the fuel pumps a lot too. I've seen v6 mercury outboards with the entire inlet side of the fuel pump full of it. It's pretty common around here.

 

[philiefay]

Would make sense to me if it was in two fuel lines but probably the best explanation I have so far.

 

[SailingLoto]

Here's some brown crystals. It's from this crappy old gray fuel line. Pretty common. Yes, it looks like dirty salt/sugar.

This one had just started failing on an 04 60hp merc 4stroke. Assuming the filter caught it before it hit the VST, we will clean the fuel pump, replace entire line/bulb/fitting

 

[philiefay]

I just wanted to close this issue for the sake of anyone else having it. I took the engine to a mechanic who said he has seen this before. Someone (prior owner) had added some water absorbent material to the fuel tank and it reacts with the alcohol in the fuel to crystalize. Hope that helps someone in the future. Seems like the most sensible explanation I have heard so far.