Is there anything I can give the petrol tank a rinse with? (petrol, not diesel)

[ChasB]

Hi,

I've got a load of old petrol sitting in my tanks which I'm about to pump out. It's not going to be possible to give it a pressure clean or anything, and the extraction will likely leave some residue behind.

Seems to me that before I put fresh stuff in I could maybe give it a rinse with something that might dislodge a bit of the crud still clinging on. Something that wouldn't later be harmful to the engine.

A rinse with a gallon of petrol seems an obvious option, but maybe there's better. Any ideas? Someone suggested 99% rubbing alcohol.

Cheers!

 

[John the kiwi]

I would rinse with methylated spirits to remove any moisture.
Intersting read here:
https://autoexpert.com.au/posts/qa/how-do-i-fix-water-in-the-fuel-tank

 

[jiris]

I would rinse with methylated spirits to remove any moisture.
Intersting read here:
https://autoexpert.com.au/posts/qa/how-do-i-fix-water-in-the-fuel-tank

I don't think water is the O.P.'s main concern. I believe he is more worried about a kind of gunk or resin-like deposits. Following a plain logic, I would use just a clean petrol, making sure I stir it properly and possibly help the cleaning process by a bit of mechanical rubbing. Warming the petrol a bit in a water bath before use may help too. The idea behind it: whatever doesn't get dissolved during this process, won't get dissolved later so it won't cause any harm. Just my 5 cents worth...

 

[Iliade]

Spray carb cleaner should dissolve any goo remaining in the tank. IIRC it is mostly xylene, which is horrible stuff, but is one of the international paint thinners. Or at least it was once...

If your tank is plastic do a test wipe on a spot outside first lest it dissolves.

Universal solvent (hot water) and washing up liquid works surprisingly well, as does a pressure washer. If it's a fixed tank use a wet & dry hoover to remove the water.

Petrol is unlikely to dissolve deposits and new 'petrol' has a lot of alcohol in it anyway. It is always best to avoid using petrol as a cleaning solvent because of its habit of incinerating anything nearby.

 

[jiris]

.......................................It is always best to avoid using petrol as a cleaning solvent because of its habit of incinerating anything nearby.

Not sure if the carb cleaning fluid is much better in this area.

"Xylene is a clear, colorless liquid. It is volatile, readily producing flammable and toxic concentrations at room temperature."

If I should be foolish enough to play with some ignition source while using either of these liquids, the main difference is with petrol I'll get incarcerated cheaper.

 

[ChasB]

Thanks folks.

These are big fixed tanks. 50 gals capacity each? The only access is via the petrol 'in' and the breather. And the fuel lines of course, but...

What about a couple of gallons of petrol with some carb cleaner mixed in? Though I like the logic of 'whatever doesn't get dissolved during this process, won't get dissolved later so it won't cause any harm.'

Cheers!

BTW I'm pretty sure that it's no longer volatile. I was thinking of taking out a small amount and putting a match to it in the car park and seeing what happened. I'll wear an insulating glove and specs just in case! Is there a better way?

 

[thinwater]

I hope you realize the process of fooling around in an empty but not clean tank is tickling a bomb. And it is NOT about how it burns on a rag, it is about the fumes in the tank. 1000:1 says the flash point is still blow room temperature.

The pump-out tube should be anti-static (fuel hose, aluminum tube, or CPVC but not PVC) and non-sparking. All equipment must be non-sparking. Fumes must be kept out of the cabin and turn everything off. I've done the accident investigations where these things went wrong. I would either power wash the tanks (non-sparking wand and nozzle) or just rinse with a little petrol. Keep it simple and consider every action. The ignition sorce on one accident was a man walking across gravel and then touching the tank.

 

[Old Harry]

Spray carb cleaner should dissolve any goo remaining in the tank. IIRC it is mostly xylene, which is horrible stuff, but is one of the international paint thinners. Or at least it was once...

If your tank is plastic do a test wipe on a spot outside first lest it dissolves.

Universal solvent (hot water) and washing up liquid works surprisingly well, as does a pressure washer. If it's a fixed tank use a wet & dry hoover to remove the water.

Petrol is unlikely to dissolve deposits and new 'petrol' has a lot of alcohol in it anyway. It is always best to avoid using petrol as a cleaning solvent because of its habit of incinerating anything nearby.

concentrated Traffic film remover would work

 

[langstonelayabout]

I hope you realize the process of fooling around in an empty but not clean tank is tickling a bomb. And it is NOT about how it burns on a rag, it is about the fumes in the tank. 1000:1 says the flash point is still blow room temperature.

The pump-out tube should be anti-static (fuel hose, aluminum tube, or CPVC but not PVC) and non-sparking. All equipment must be non-sparking. Fumes must be kept out of the cabin and turn everything off. I've done the accident investigations where these things went wrong. I would either power wash the tanks (non-sparking wand and nozzle) or just rinse with a little petrol. Keep it simple and consider every action. The ignition sorce on one accident was a man walking across gravel and then touching the tank.

When I needed my Catalina's alloy tank fixing I got a company to professionally clean it before fixing it. Well worth the GBP 25.00 or so, even though it had been full of diesel.

I recently cleaned out some petrol-filled Jerrycans. Got rid of all the petrol, cleaned out with boiling soapy water and then a pressure washer. Well worth the hassle. No eyebrows singed.

Petrol vapour. Be very afraid. Treat is as the risk that it really is, not the annoyance you think it could be. Drain the lot, remove the tanks, fill with water and go from there.

 

[thinwater]

This is a criminally bad idea with petrol. We took a guy to hospital that tried that. Yes, after water washing. He must have misses a little petrol. We were still finding parts of the Hoover years later, far away. Such it out with a manual oil vacuum (no spark).

FWIW, vacuum trucks are used to remove flammable liquids, but the vapor does NOT go though a sparking motor and there is a list of safety precautions as long as your arm. Different.

 

[Iliade]

This is a criminally bad idea with petrol. We took a guy to hospital that tried that. Yes, after water washing. He must have misses a little petrol. We were still finding parts of the Hoover years later, far away. Such it out with a manual oil vacuum (no spark).

FWIW, vacuum trucks are used to remove flammable liquids, but the vapor does NOT go though a sparking motor and there is a list of safety precautions as long as your arm. Different.

Head hung in shame...

 

[thinwater]

Head hung in shame...

I didn't mean it that way, but the injury potential is real.

The best way for most boat owners to move petrol is by either shaker siphon, manual oil extraction vacuum, or a combination (oil vacuums are great for starting syphons).

I worked in the refining industry for 35 years and saw some bad accidents and some serious close calls (something blew up but no one was injured). Petrol can be handled safely, but you have to follow the rules, most of which have to do with minimizing vapors and eliminating any chance of spark, inducing static.

 

[jiris]

.............................................
What about a couple of gallons of petrol with some carb cleaner mixed in? ................................

I think the carb cleaner is totally redundant. The reason of it being used on carburettors is, it dissolves deposits petrol doesn't. Just a fraction of mm of such a deposit inside of some of the delicate passages inside a carburettor can severely impair its performance. We don't have this problems with the tank. Who cares about some kind of varnish one the walls? If it doesn't get dissolved by petrol affecting its quality, it is harmless.
I would also add my voice to the posters warning about the danger of explosion during the cleaning process.