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ideas on fixing - one carb keeps "rusting"

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tdskip

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ideas on fixing - one carb keeps "rusting"

Hi guys - I am getting that white crud after cleaning my carbs to a point where it is preventing the pistion from moving freely. I've soaked them in carb cleaner for a couple hours and generally cleaned them. No different than usual.

Ideas?

Thanks
 
Re: ideas on fixing - one carb keeps "rusting"

I assume it is aluminum oxide in the upper -non fuel part of the carbs. If that is the case you might try some aluminum prep and small brushes. However, if it is aluminum oxide and if there is enough residue to hinder movement, there has got to be some pitting somewhere. Perhaps time for a complete rebuild.
Tom
 
Re: ideas on fixing - one carb keeps "rusting"

On SUs that oxide build up is normal on the outside but fairly uncommon on the inside because that area is excluded from the elements. I can't think of how you would develop that corrosion on the inside of a carb that sees at least occasional use.

However, my suggestion would be to clean them one more time and then neutralize the surfaces by washing the carb parts with baking soda disolved in water. Rinse that off and blow/wipe inside and outside dry. Finally, before reassembly, spray the outside of the carb piston and inside of the SU vacuum chamber with silicone spray (not WD-40... silicone spray). Wipe off the excess and reassemble. Of course, make sure the steel tube on the piston and steel bushing inside the vacuum chamber are rust free and lightly lubed during reassembly. The silicone should stay in place on the interior surfaces and exclude moisture from reaching the metal.

If these are Strombergs, I can think of no way for surface aluminum corrosion to cause sticking... unless the carbs were left under water for a while!
 
Re: ideas on fixing - one carb keeps "rusting"

Hi guys - thanks for the responses.

These carbs did sit for a long time judging by their condition, which isn't a big deal usually. They are totally apart and as part of a rebuild already - they where like this when I started cleaning them but I've never had it happen after they there cleaned and soaked.

Doug, they are SU HS6 but that shouldn't make much of a difference.
 
Re: ideas on fixing - one carb keeps "rusting"

Hi guys, the only time I've seen this when they've sat in humid or wet . Not on a running car. Kevin
 
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