Stripping carbs, weird residue

I stripped my TK-22 carbs so that I could repaint them. All the carbs but one came out clean. I used a gallon of carb dip cleaner and let them sit in there for a few days.

The one carb has a dull, gray metallic residue that comes of on a cloth or your finger if you rub it. I've tried a degreaser, elbow grease and spray carb cleaner but I can't get it as clean as the other carbs.

Any suggestions?

Maybe soda blasting. Harbor Freight has a kit.
Make sure to seal off any small openings, especially inside the air horn, and in the main port.

I can't recall if carbs #1 and #2 can be swapped, but if they can, maybe try to put that carb as #2, ( make sure the choke rod still turns smoothly).

The discoloration occurs when you leave the carb in the dip too long. It also occurs if you boil the carbs in lemon juice or similar.

Agree with the soda blasting technique. They will look so nice and shiny you will be hesitant to paint them afterwards.

Nessism wrote: The discoloration occurs when you leave the carb in the dip too long.

Yep. I only use carb dip for an hour or so on aluminum. It eats it if left too long. I ruined an H1 petcock once when I forgot and left it in for a week. It looked like it was melting...

Thanks guys

ThatGPzGuy wrote:

Nessism wrote: The discoloration occurs when you leave the carb in the dip too long.

Yep. I only use carb dip for an hour or so on aluminum. It eats it if left too long. I ruined an H1 petcock once when I forgot and left it in for a week. It looked like it was melting...

Just a little FYI: most carb bodies are zinc.

Same thing happened to me. It was as said, leaving the carb in too long. I actually think the carbs are coated with something and it eats that off.

Soda blasting was the trick although that coating will be gone for good.

Did you repaint your carbs? I'm looking at Gun-Kote or Aluma-Hyde for my carbs and calipers.

ydb1 wrote: Did you repaint your carbs? I'm looking at Gun-Kote or Aluma-Hyde for my carbs and calipers.

I just soda blasted them to get them even coloured.

In Canada I don't have access to aluma Hyde but it sounds really good when I read about it. I like when stuff looks fresh. But I have seen a lot of false claims on aerosol paints.