Why is there glue on my caburetors?

Hello John

Excellent question and I have an answer for you.  The production of the carb requires drilling passages into the carb body.  The end of the bore it is then sealed by pressing in a ball as you have seen.  The last thing they do is put on some clear epoxy sealer over the ball to be sure that no air leak will be at that channel end.  

Now that you know that remember that it is not a good idea to use ultrasound cleaning on carburetors.  There is the risk that the ultrasound may cause the epoxy to drop off in some areas and after that you forever are struggling with sealing air leaks in the body.  If you have worked with Rotax Bing carbs for a long time we can recall they went from a raw casting for the body to one with  dark grey appearance.  That is actually a Loctite bath that the body has gone into that helps to seal tiny imperfections in the casting that can cause leaks.  Should you have to ever do carb work always check the body for any sealing balls that might be missing that epoxy.  Replace it, this can be very important. 

Cheers

Awesome - thanks for the quick reply!

Very interesting RW!

I don’t suppose I have ever noticed any epoxy (or similar) spots on my carbs. Do you mind writing a couple of words on what effects potential air leaks at these spots would produce?

in case one does not find the epoxy sealing spots on one carbs a drop of Loctite would do the trick, too, right?

Hi Peter

The only type of Loctite that might substitute would be something like Loctite 290.  This is for assembled fasteners and the 290 is put on the parts after, on the edge of the bolt to nut or bolt to casting.  It should "wick" into the threads.  Epoxy sealants should be easy to find however, they have a lot of good uses.  I note you are in Germany so try Liquid Moly products, they are made in Germany.  

https://tech-beac.com/en/industrial/maintenance-chemical/adhesive-and-sealants/epoxy-adhesives/liqui-moly-epoxy-adhesive/

Cheers