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Cork Float in 1922 Marvell Carb

David Marshall

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Good afternoon (NZ time anyway)  The last issue before my car will drive without flooding.   We pulled the carb apart and have found the issue of constant flooding after running great for 3 or 4 minutes.  It appears to be the float - ( cork ) has become dry and porous.  Have read in this forum the answer is to replace it.   I have searched NZ and phoned all the old car experts and parts stockists to be told, mmmm no sorry.

Is there a place to buy a replacement float OR does anyone know what I can seal it with please ?


On a side not, someone in the last 98 years has wrecked the crew that holds the float hinge pin.   Is there any trick to getting it loosened.   I was told to give in couple of good belts with the correct size drift and then heat the area with a heat gun (For paint stripping).  Hopefully this will get it loose enough.


Does anyone know what the size screw is incase we have have to drill it out - last resort of course.

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20201007_174814.thumb.jpg.3b1a49061fd2b774b7c0f45f8ee447c7.jpgDavid,  Read what Mark Shaw has written about Marvel carburetors, in the topic 1925 Buick Master six convertible in this Pre War section.  You can make a new float from wine bottle corks and glue them together.  Others on this Forum have said model aeroplane glue won,t  dissolve in petrol with ethenol.  This 1920 carburetor float pin,  the thread is 5.5mm/ 7/32inch outside diameter and the pin is 2.7mm diameter.  I would think the 1922 pin would be similar.

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David - I have had zero positive results in attempting to reseal a float which has previously been in fuel.


Balsa wood may be used for a float (hobby shops).


Have never tried the wine corks (might be enjoyable acquiring the corks ;) ), but walked by the wine display in the grocery yesterday, and happened to look at the prices. Ouch! Glad my favorite beverage is tea!


Should you machine a new float from either the above, the dope used to coat the fabric on model airplanes will seal the float.


As to your float pin, once you have removed everything from the bowl that heat will hurt, heat the area around the float pin with an acetylene torch; the heat gun does not supply sufficient heat.


As mentioned by Rod Wise above, the thread diameter is 7/32" and the thread pitch is 32 threads/inch. This was a favorite thread with Marvel. The part number for the pin is 33-501, and is a part that surprisingly, was used on many of the early brass Marvel carbs. Possibly a junk donor carb could be found to donate a good pin.



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Carb float material
I have a 1924 Buick 24/34 which uses a Marvel carb with cork float which over time had become saturated with fuel. I tried making a new float from cork and treating it with clear fuel proof model varnish to no avail.
The solution was a float made from ethernol proof material obtained from the following company in the USA. Restorationstuff.com.
They stock not only floats for some vintage vehicles, but also blocks of float material that can be cut/machined to shape.
The replacement float was 30$ + postage and has been on my car for over 6 months and is functioning OK and does not appear to be affected by unleaded fuel.

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