What solvent to dissolve goop in bottom of 2 stroke fuel tank

[Keith-i]

I'm giving an old but lightly used Mariner 5hp outboard a pre-season check and noticed a good helping of red oily goop in the bottom of the fuel tank. I've seen this before in 2 stroke tanks and assume it is some oily deposit from the 2-stroke mix. Anyway, question is, what can I use to dissolve it and clean it out. I've tried petrol, parafin, carb cleaner and Gunk but nothing softens it enough to clean it out. Any thoughts?

 

[davidej]

Cellulose thinners? Shifts most things!

 

[Rum Run]

Try methylene chloride perhaps, it shifts things that cellulose thinners or even acetone won't. I haven't tried it in a fuel tank mind you.
Do not get it on gelcoat!

 

[onesea]

If it's not easily dissolving in petrol, maybe just use the tank. It will either stay put or gradually dissolve back into petrol and be burned.

 

[penfold]

Try meths or isopropanol, they will shift stuff others won't. I'd also try very hot or even boiling soapy water with some gravel or nuts or ball bearings and give it a thorough shake with the cap on.

 

[Refueler]

Sounds like someone has left the tank to vapourise off leaving the 'goop' behind. Then its hardened and then hard to remove.

Forgive this question ... but just to be sure.

Are you sure there is 'goop' in tank .... as its quite common for plastic tanks on garden machinery / outboards etc. to get a reddish or blueish stain in the bottom level of tanks from fuel left standing in the tank. When its bad - it looks like a layer actually in the tank until a really good look into tanks reveals its staining. The stain is from the 2T oil and various blend components in the gasoline.

OK - so its really a layer in bottom of tank ...

May I suggest that any 'mechanical attempt to remove - such as inserting a rod or similar to break the 'goop' is a bad idea ... you may dislodge chunks you can remove - but you may leave behind smaller particles that can then cause fuel draw problems.
Softening of the 'goop' can also lead to passing through fuel system ...

Me ? I would leave it well alone and see if use of the tank reduces it slowly .. unlikely - but if tank is used often - little or no further build up should occur.

IMHO.

 

[Keith-i]

Cellulose thinners? Shifts most things!

Thanks, I hadn't thought of that.

If it's not easily dissolving in petrol, maybe just use the tank. It will either stay put or gradually dissolve back into petrol and be burned.

Thanks but not an option - see below

Are you sure there is 'goop' in tank .... as its quite common for plastic tanks on garden machinery / outboards etc. to get a reddish or blueish stain in the bottom level of tanks from fuel left standing in the tank. When its bad - it looks like a layer actually in the tank until a really good look into tanks reveals its staining. The stain is from the 2T oil and various blend components in the gasoline.

Me ? I would leave it well alone and see if use of the tank reduces it slowly .. unlikely - but if tank is used often - little or no further build up should occur.

IMHO.

It's definitely not a figment of my imagination. It's akin to runny honey and there was enough in there that some of it made its way down the outlet and clogged up the fuel valve. I'll try some other thinners but don't want to damage any plastic or rubber components in the process.

 

[Refueler]

OK ... now we have a bit more info ....

Runny Honey ..... mmmmm

Cellulose Thinners .... be very careful with that and any similar product - many plastics / rubber will not tolerate it ...

I think if the tank can be removed ... and you can seal up 'holes' .... then old gasoline and clean gravel shaken about in the tank would be my thought ...

Your last post illustrates similar to what I was concerned about - 'goop' getting into the fuel system.

 

[Momac]

Is a new fuel tank not an option?

 

[Alex_Blackwood]

I'm giving an old but lightly used Mariner 5hp outboard a pre-season check and noticed a good helping of red oily goop in the bottom of the fuel tank. I've seen this before in 2 stroke tanks and assume it is some oily deposit from the 2-stroke mix. Anyway, question is, what can I use to dissolve it and clean it out. I've tried petrol, parafin, carb cleaner and Gunk but nothing softens it enough to clean it out. Any thoughts?

Fairy Liquid and boiling water???

 

[Fr J Hackett]

There are two types of organic solvent polar and non polar, they work to dissolve substances in a different way. Petrol is non polar like many of the hydrocarbon solvents suggested alcohol is polar and may work. However where has the residue come from? Answer the original petrol 2 stroke mix so it must have been soluble to an extent in petrol so petrol is the solvent to remove it but it will take time as refueller suggests the best option is leave well alone and if it eventually gets dissolved in new petrol all well and good if it doesn't it appears to be doing no harm so leave well alone.

 

[Keith-i]

Thanks everyone for the input. I ended up trying acetone which dissolved it enough to rinse out and unclog the fuel valve. All working well now.