Classic cars forum & vehicle restoration.

[Bitumen Boy]

What's a good solvent to shift stubborn gum or varnish that may or may not be in a carburettor? I've heard of the bodies of older carbs (it's a Solex that's giving problems) dissolving in modern cleaning solutions, so obviously want to avoid this happening! I've had the jets out several times and blown everything through with compressed air but have only improved matters up to a point and suspect there's something lurking there still...

[RUSTON]

Years ago we used to soak the carb in cellulose thinners, cleaned them out a treat. Nowadays, in this H&S obsessed world, I couldnt say what was best!

Pete.
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Measure twice...cut once!

[Bitumen Boy]

Thanks Pete, it just so happens I have plenty of celly thinners, so will probably give it a try. It's from rusted cans and has lots of fine rusty sediment in it so not much good for anything else except brush cleaning, but a little sediment's nothing some air won't sort out. To digress a little, I've been keeping the stuff in old cider flagons - just what was handy, you understand - and it's amazing how much it looks like scrumpy, never drink anything in my garage without sniffing it first

UPDATE: Pete, I soaked it in thinners for half an hour - it was a warm day & I didn't want it all to evaporate - before blowing it through again, do you reckon that would have been long enough to shift anything that might have been there?

[Handyman]

Try soaking the parts in biological detergent, you know, the stuff you wash nappies in. The enzymes in the solution seem to relish all those nice gummy deposits. Sometimes a little heating of the solution also helps.

H

[47p2]

Another job for the dishwasher when the wife is out of the house
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ROVER
One of Britain's Fine Cars

[Handyman]

Owww! Naughty! Swmbo will find out, they always do.

[PAUL BEAUMONT]

A friend of mine goes on and on about the improvement in performance from his car after having the carb cleaned in an ultrasonic bath. He says that he was amazed at the gunk that came out!

[Bitumen Boy]

Thanks for the further replies on this one, guys. I hope I can track it down to something else, but you never know...

Handyman, your advice on the bio detergent is interesting. What sort of concentration would you reckon on, or isn't it too important? And when you say heating, how much - blood heat, or a little more? Presumably the enzymes would be killed by boiling. I did think of boiling it up with soda but was too chicken!

47p2, what's a dishwasher? Seriously, I don't think anyone on this street has one, and if they did I can't see them agreeing to a mucky old carb in it, the old cars parked/driving on the front street nark most of them off as it is.

Paul, I can see how the ultrasonic bath could help, but again, I haven't got one or know anyone that does, could be a laugh to put an ad on Gumtree or Craigslist though, I bet someone would think it was a euphemism for something dodgy! I'm guessing your mate must be "in the trade" to have access to one, I'm just wondering which trade - don't dentists use them..? Nice idea though!

Thanks again to all

[clan chieftain]

I use brake fluid on the SU.
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The Clan Chieftain

[exbmc]

I think most S.U. dashpots and pistons were polished up with brake fluid. We have a small (6 litre) sonic bath for cleaning small components, such as gears, rockers, magneto bodies, and the odd piston. Carb bodies also come out well when stripped for overhaul.
Something like this will cost about £100, and you will wonder how you managed without it, if you clean small parts regularly.

[ukdave2002]

[Bitumen Boy]

Thanks for the offer, Dave - much appreciated. But seeing as I'm away down in old Monmouthshire, it's a bit of a hike and probably a last resort! I think I've seen NOS examples of this particular Solex go for less than the petrol would cost me for that trip, OK probably not if I wanted one but it kind of puts it in perspective.

I don't clean small parts very often so couldn't justify the expense, but I just had the wicked thought that maybe I could con my dad into getting one for cleaning his dentures...

[Bitumen Boy]

Still having problems on the carb front. I tried soaking it in bio detergent, but think I left it too long and ended up with it covered in a stubborn white deposit - it doesn't seem to be corrosion, my guess is it's basically sodium carbonate (most wash powders seem to be very little else) but you'd never guess from how difficult it is to shift. I've got it off the outside of the carb by boiling it up several times and scrubbing with an old toothbrush, but it seems to be bunged up internally despite my best efforts with pipe cleaners and compressed air - the jets are fine, but the fine drilled passageways are another matter entirely. Any ideas what might shift it?

The spare carb, typically, has a leak that I can't seem to fix - suspect a crack in the body - so is US as well. Going nowhere at the moment

[47Jag]

BB

Why don't you post the carb. to Dave and let him clean it for you?

Art

[Churchill Johnson]

This subject has been raised before but i will answer it again i use some stuff called gun wash its for cleaning paint from spray gun's and is very effective put a stripped carb into this but in an airtight container as it will evaporate very quick it will shift any gum deposit's, but be warned do not get it on your skin or breathe any vapour's it is listed on the net with a list of the chemical's it contain's, there is another issue with it which you will be able to see on the net something about hindering baby production you have been warned.