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MG MGB Technical - Cleaning inside a carburettor
|Is anything recommended for cleaning the insides of a gummed up SU carburettor? The picture shows a mirror image of one of the SU HIF float chambers viewed from underneath.
|I boiled mine in 1:3 CLR ("Calcium, Lime, Rust" product. It is mainly citric acid. Rad cleaner is probably the same. If in doubt, try it on a piece of ally scrap and brass and steel. It worked great for me. Do not use anything caustic, including TSP, it will dissolve it. Vinegar would be a choice also.|
|Carb cleaner is usually the best option!|
|Chris at Octarine Services|
|Chris I have looked at a selection of products for cleaing carbs but find the advertising a little confusing.Some of the products seem to be for the outside of the carbs and some to add to the petrol to help clean as the car is driven.|
I bought some Redex to try as a fuel additive but would it be the sort of cleaner to use to wash the parts? Can you recommend a particular product?
I have wondered about buying an ultrasonic cleaner (I have seen them advertised for as little as
An aerosol can of "Throttle Body Cleaner" - used regularly on injected cars and available everywhere. (Paraphrasing Chris's reply.)
|Aerosol carb cleaner, it is high-pressure so blasts gunge off as well as the solvent action.|
|What can I use to clean up the outside and inside of a badly oxidized set of carbs?|
|I always use methalated spirits to get rid of gum|
|Anybody ever tried an ultrasonic cleaner?|
I have used mine on Webers and SU's for many years now.
A great way to clean jets and vents / emulsion tube assy's etc.
Cleans linkages without the need for total disassembly too and is really good for heim joints and throttle spindle bushes.
Cheers , Pete.
What sort of capacity would you recommend for an ultrasonic cleaner?
Would it work simply with water or would it require any special chemicals?
|If the surface is 'badly oxidised' then it's going to need polishing.|
|Or bead blasting. Keep away from the internal surface of the suction chamber and the edge of the piston itself, these are precision machined and must not be abraded.|
If the carbs are that bad, find a better set or exchange them.
|Chris at Octarine Services|
|My carbs are in very good unoxidised condition (only filthy inside the float chambers because of gallons of decomposed petrol)and I want to keep the original metal die cast look. |
Rather than opt for the 'newly sand cast' look which -to my eyes - bead blasting imparts, ultrasonic cleaning appeals to me because (I understand) it is utterly thorough yet non destructive of the original finish and works inside and out.
Is this correct Pete?
Sorry for the delay in replying. I have had server problems off and on for the weekend.
No special chemicals needed for the ultrasonic cleaner but some sort of detergent is helpful to get grease and dirt out of small crevices etc.
I use dishwashing detergent and hot water. Let it soak for about five to ten minutes in the u/s unit then turn it on. The amount of rubbish coming out is usually astounding.
I normally clean the item as best I can with degreaser first and leave the ultasonic to do the detail stuff.
Sam , you are correct is saying the ultrasonic unit cleans in side and out and leaves the finish untouched.
Where ever the water is the sound waves will travel and vibrate loose whatever dirt and debris is there.
This includes internal passages and jets.
My unit is a small table top model and holds about a coffee cup full. Larger items sometime need to be done in stages but so far it works well enough.
It came from a local electronics place and cost about AUS$50.00 (UK 20.00 Pounds or so)five years ago.
One item worth making is a small basket to hold the items to be cleaned off the bottom if the unit.
Mine is made from scrap metal flywire screen and a wire coathanger. Leaving some space lets the debris fall clear and the flywire screen is small enough to hold just about any part. Works well for rings and brooches too!
Cheers , Pete.
I have ordered an ultrasonic cleaner so I hope to be able to report on progress in the next few days.
Can an ultrasonic cleaner do any harm to a carb?
|I will try a throttle body cleaner too - to be sure.|
Short answer: NO.
One caution: Never run the ultrasonic cleaner empty even for a short while.
The damage done is not usually fixable and the life of the unit will be shortened considerably.
By the way you may find a lot of jewelry owners (wives , girlfriends , sister and sisters in law) will become your friend for life when they find you own one of these.
Post how you go with it.
Cheers , Pete.
|I use MEK and a small acid brush. I trim the acid brush brisles to 1/4 inch for stiffness. Gets rid of varnish in short order After the varnish is softened I wash the parts in mineral spirits. Use MEK in a well ventilated place unless you want to go on a trip. If I use carb cleaner the wife locks me out of the house until I clean up and wash my cloths. I have tried bead blaasting and the beads keep showing up long after I have assembly the carbs. I now only bead blast the outside surfaces.|
|Ermit I don't know if MEK is readily available in the UK but one source suggests cellulose thinners as a cleaner though I wonder how the plastic float would react.|
My ultrasonic cleaner has arrived and after a few tests I will try it out on one of the carbs.
|Cellulose thinners certainly works very well. I have used it for years with great success. It simply strips off all the external dirt and leaves the carb shining like new. Whilst I would noe advocate its use on plastic floats it doesn't seem to have any adverse affects on them|
|It's amazing how difficult it is to get stuff these days. I remember as an 11 yr old walking into the high St. chemist and buying diethyl ether, amyl nitrate and nitromethane for model aero fuels.|
|I have been having a go with the ultrasonic cleaner. The piston and needle are seen just before cleaning. These carbs had been OK but became badly gummed up with old fuel so I felt I did not need to disturb the needle.|
This is the 'before' picture.
|This is during the ultrasonic cleanig process. I used warm water with washing up liquid.I repeated the cycle several times.
|This is the result.Not perfect yet but I find it acceptable. Some of the black staining on the aluminium was removed by hand with a sponge and more washing up liquid and warm water. |
It is possible thinners or other solvents could have produced similar results but the crust on the needle was removed purely by the ultrasonic cleaner.
It is good to hear you are having the results you want with the U/S unit.
One plus with them is they allow you to get on with other things while they do the cleaning.
Remember to angle any pieces with internal passageways to allow the loosened rubbish to come out. Otherwise it just stays where it is.
Cheers , Pete.
This thread was discussed between 07/08/2009 and 17/08/2009
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