cleaning an iron carburetor

2manycars

2manycars

Well-known member
Will muriatic acid clean the rust and goop out of a cast iron carb? If not, what will do it. I used to be able to get some strong stuff from napa, but can't get it anymore. It was strong enough to eat through the can in a few years.
 
Unless you watch it I think the muriatic acid will be too harsh and will require a thorough rinsing and neutralizing. I spilled some on workbench, not realizing it and it raised h--l with some of my good wrenches, now all rusty.
Paul in CT
 
It is my preference to glass bead the cast iron parts after a complete disassembly. I then use hot soapy water and high pressure air to remove the imbedded glass beads. PPG's DP-90 (Black) epoxy primer is my finish of preference. Gar Williams
 
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You can still get a quart can of carb cleaner. It comes with a basket to put your parts in. Lower it in the can and let it sit for a day or so. Works great. I get it at the auto part stores. Jon
 
I have cleaned ordinary rusty steel parts using hydrochloric acid (muriatic) without any problem. As an experiment I left a cast iron carburetor bowl in the acid for a day or 2 in hopes of loosening up an inner well. The result was that the acid softened up the cast iron so that it could not be used.
 
I do not like the surface effects of HCL or vinegar at all...nasty, grainy, hard to neutralize. Phosphoric (used in many commercial derusters) gets rid of the rust and leaves a much better, more original surface and seems in general to have no vices.
Glass beads require much work with soap/detergent to clear out...usual solvents are no good, and a few beads can do a lot of damage if they get into engine. Do not assume a swizzle in carb cleaner got rid of them!
 
marc hildebrant said:
Phosphoric Acid is found in Coca-Cola.

Works good on Chrome too.

Marc
Click to expand...

Brilliant! I had forgotten the old coke dissolving rust ploy. They add the phosphoric acid to enhance the fizz of the carbon dioxide. Rots holes in your stomach too, with too much indulging.
 
Define "Goop". If goop is actually dried up gas and varnish, I say 'NO'. Muratic & Phosphoric will not attack organic items. For that is takes a caustic. Hot caustic if aggitated within the part will also do a slight job of making loosely attached rust release. I have a large Caustic vat that we operate at about 175° and it is "tough on grime"!!

Phosphoric acid in a diluted solution (10%-15%) is available in the paint department in stores like Home Depot & Lowes. My Lowes carries it under the brand name Jabsco. It needs to be placed in a non-metalic container. Caustic is available in powdered form from janitorial supply houses and chemical supply houses. Depending on strength, both of these can be very harmful to your health!!

One other tip, ...I have several old crock pots that have been purchased at garage sales for less than $10 each. Carefully heating the caustic solution and soaking the part allows the chemical to be really aggresive at removing varnish, paint, gum, and anything organic. Heating Phosphoric Acid also rapidly increases the potency on its de-rusting ability. Just remember what you are messing with, as it can hurt you if you are "stupid" with it!!!


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I have ran a tractor repair shop for many years and always soak cast carburetor bodys first in common carb cleaner to remove the goop then rinse well then soak for an hour or so in a 50/50 solution muratic and water. Have rebuilt hundreds of carbs without a problem. I always have a bucket of very hot water ready when I pull them out of the acid solution, let them soak in the water long enough to make them too hot to handle then blow dry. Get some wd40 or similar on quickly to prevent rust. Oh and one more thing never store muratic indoors as it will cause most everything in your shop to rust.
M&M
 
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