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SOHC.co.uk Forums => Anorak's Corner => Topic started by: DomP on April 06, 2025, 08:23:11 AM

Title: Flushing old fuel
Post by: DomP on April 06, 2025, 08:23:11 AM
I've picked up a spare tank for my 550, it's got ancient stinking fuel left in it and I can't get the last bit out before doing any work on it.  Other than diluting it with fresh petrol what else can I use or do to get it out?
Title: Re: Flushing old fuel
Post by: K2-K6 on April 06, 2025, 09:34:05 AM
Most solvent, like white spirit etc will flush out. You'd just need to swill with fresh petrol before use again.

If you've a wallpaper steamer, that'll also help clean out if you just put the pipe end inside tank and point at various crevice etc..
Title: Re: Flushing old fuel
Post by: DomP on April 06, 2025, 09:37:23 AM
Id never thought of a wall paper stripper, that's a good idea.  I've never smelt old fuel this foul before.
Title: Re: Flushing old fuel
Post by: McCabe-Thiele (Ted) on April 06, 2025, 09:54:36 AM
The 12 year old petrol in my 400 tank was awful, it was an almost black tar like gunk. The steamer sounds a great idea btw. The last remnants I removed with glass gravel (wife's flower arrangement
left overs) and white spirit. Final stage was Evaporust.
Title: Re: Flushing old fuel
Post by: K2-K6 on April 06, 2025, 09:55:24 AM
Yes, it can be pretty stinky can't it  :)

That is the more diesel like component that does the donkey work in combustion, and not very volatile either. 

The more volatile, and easily identified when its fresh has got up and liberated itself as part of its character to get the spark ignition going consistently. 

Steam is often used in chemical lab to clean all the glass vessels of contamination safely and pretty effectively too.
Title: Re: Flushing old fuel
Post by: DomP on April 06, 2025, 11:27:32 AM
To derust i was going to use phosphoric acid
Title: Re: Flushing old fuel
Post by: Laverda Dave on April 06, 2025, 12:13:38 PM
Or DEOX-C, it's great stuff👍.
Title: Re: Flushing old fuel
Post by: McCabe-Thiele (Ted) on April 06, 2025, 03:05:37 PM
To derust i was going to use phosphoric acid

I've just been de-rusting a pair of exhaust brackets  on my Superdream ( Evaporust is expensive).
I've tried some warm Citric Acid instead, pleased with the results. I found agitation with a brush was needed.
Title: Re: Flushing old fuel
Post by: Athame57 on April 07, 2025, 02:17:27 PM
I've never smelt old fuel this foul before.
You havn't met up with the Bunker oil they use to fuel merchant ships! It is like a gas attack when the smell is released for whatever reason, intensely reeks of rotten eggs for a start,  :o I once fled my cabin with some bedding and joined others at the opposite end of the ship!   ;D
Title: Re: Flushing old fuel
Post by: Bryanj on April 07, 2025, 04:03:45 PM
Good old heavy fuel oil, used to run 150 ton per day on one ship. Wont burn till heated up