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Substance for Dissolving Calcium like Deposits in Carburettors

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  • Substance for Dissolving Calcium like Deposits in Carburettors

    As in title ..

    is there anything out there that will desolve these deposits ...without effecting brass of the magnesium alloy castings.

    this is about my work on the two Honda c70's of just bought.

    spent a lot of time unblocking jets them out etc.

    tried ultrasonic cleaner it didn't work...nor did air or degreaser

    resorted to wire...but have feeling the wire didn't push every thing out jet is 0.35mm...wire wouldn't of damaged it really as it is quite long about 3/4 of an inch....i will replace them with new sometime ..

    so what's the chemical called ...and what are these deposits ..that i call calcium .

    found varius reference around the net to something called CLR

    but not seen this stuff in the uk

    all the best..markj
    Last edited by aboard_epsilon; 07-28-2012, 07:24 AM.

  • #2
    sounds like aluminium oxide, if the carbs are ali, if so then an alkaline solution will clean, add pearl caustic to water SLOWLY, a metal container like an old stainless saucepan works well, solution will get hot, enough to melt through a bucket [ my version of the china syndrome], dip them in on string and the surface will etch/ deposit dissolve, good for etching ali and stripping paint too!


    • #3
      im going into see if there is such a thing as calcium lime rust remover here under another name perhaps.

      all the best.markj


      • #4
        Not being a chemist I can't tell you what it is but it's not calcium in the sense of water and aluminum corrosion. It's a byproduct of gasoline. I'm sure you're referring to when pilot jets get plugged. When a carburetor sits for a long period, with the new fuels generally longer than 6 months, the fuel will evaporate and leave that carbon byproduct in the jet. I like you have tried motorcycle specific carburetor cleaners but they won't penetrate such small orifices. I have made up a set of 'pricker wires' from piano wire. They are soldered into a small brass piece which serves as a handle. The smallest is around .008 (.2 mm). I use these to poke through the jet and then let is sit in carb cleaner for an hour or so.
        I have never seen any buildup in the needle or main jets, just the pilots.
        In the fall before I put my bikes away I fill the tank and drain the carbs. On my mowers and such I run them till they stall so there's not much fuel left in the carb. On bigger pieces of equipment I fill the tanks and put a fuel stabilizer in it.


        • #5
          i`m not sure if you can still get it(been a while since i purchased any) but i used to use a product called Berryman`s Carb Dip - came in a gallon can- about 5 minutes in the stuff would dissolve any gunk.


          • #6
            this had been stood for 16 years ..even the main jet was plugged ..

            i had to straiten out a spring similar to a biro spring to do the unplugging on the small jet.

            all the best.markj


            • #7
              I would not use CLR. There are some very small holes in those little carbs and if you etch them away they will never work right again.

              Two things I use on them are white vinegar or lime juice. But even then it is a guess. The problem with them is not plugged jets, they can be unplugged, it's the buildup of the "white" stuff in one or more of the very tiny passageways drilled in the carb. Once those become eaten away it's usually to late and I consider the carb junk.

              Honda thinks very highly of those things and a new one, if you can find one, is in the $150 price range. What a lot of people are doing is fitting a Chinese carb from one of the clones being made. They can be found on ebay or my favorite site for little Honda parts,


              • #8
                I have soaked a dis-assembled carb in mineral spirits over night then used an ultrasonic cleaner with mineral spirits OUTSIDE for several cycles until the fluid was slightly warm. Worked like a champ on outboard and chainsaw carbs.

                Last edited by boaterri; 07-28-2012, 11:04 AM. Reason: spelling


                • #9
                  Sounds like you need a 0.35mm drill bit.



                  • #10
                    It isn't likely calcium. A very common additive in unleaded gasoline is MMT (methylcyclopentadienyl manganese tricarbonyl). It will leave manganese deposits in carbs that are light coloured. I don't think there is an effective chemical method of removing it.
                    Free software for calculating bolt circles and similar: Click Here


                    • #11
                      "if the carbs are ali, if so then an alkaline solution will clean, add pearl caustic to water SLOWLY"

                      While this might work, you have to understand that pearl caustic (sodium hydroxide, ie lye) solutions eat aluminum for breakfast and produce hydrogen as a byproduct. Pretty quickly I might add. Approach with extreme caution. Magnesium, not much better.

                      Finest regards,



                      • #12
                        I'm on the second carb now on the later cub (i bought two) ..there is about 7 years difference between when each was last run ..

                        the first one was last ran, 7 years before this one

                        this one has completely different deposits in it ..

                        like varnish.

                        the first cub is now running sweetly.

                        all the best..markj


                        • #13
                          I've seen these whitish deposits in elderly carbs. It is not likely to be calcium-based, but possibly an aluminum or zinc compound, depending on what the carb body is made from. This is supported by the fact that there is often some pitting of the body in the same area. If it is a mineral deposit, organic solvents aren't going to be much help. The last time I saw these, a Phosphoric acid dip did the trick.
                          For just a little more, you can do it yourself!


                          • #14
                            Phosphoric may do it......

                            Sounds like (without seeing it) a corrosion product related to water/humidity. Those tend to cause other problems besides just the gunk, so be prepared for the carb to still not be good afterwards. Think of the stuff as "zinc casting rust", and you will get the idea.

                            The last comment on varnish seems odd though, does that refer to the same stuff? Because varnish can have flaky stuff also, of "light color", and the ticket there would probably be a solvent.

                            Keep eye on ball.
                            Hashim Khan


                            • #15
                              no corrosion in there ..once the deposits are removed the magnesium is like new pitting .

                              they are both clean but for the idle orifice on both ..this is proving impossible to clean .

                              shown here ..the smaller hole of the two..pic looking down the slider hole ..this picture is not mine ...but shows how it should be .

                              i cant see through mine nor get anything down it ..its solid

                              all the best.markj