Volume control screw.. ed me!

[cascade.king]

So I dedicated a few weekend hours to rebuilding my Zenith 32NDIX today. When I got my Hafi, the carb was loading up badly when the throttle was pressed. You could see fuel pour into the right side throat, and none in the left side.
So..
Disassembled, soaked all metal parts in a parts cleaner bath (20 mins per dip) and brushed and reassembled.
Used the Hafi NDIX rebuild kit sold by SAV, for what it's worth.
Things came apart OK, and went back as before. Bowls were a mess.
It's all clean now.

Before;

image.jpg (47.45 KiB) Viewed 1660 times

After;

image.jpg (44.91 KiB) Viewed 1660 times

So here is my problem;
The carb had a mystery left volume control screw installed. Upon review, it looks like a Solex screw.
I have 2 new and correct volume control screws now.. and they were the last pieces installed.
Right side went in just fine, but the left side was apparently damaged by the incorrect threads on the bodge-job Solex screw. The new unit will NOT screw in.

Do you folks think a tap with the correct thread size (if you know this, please tell me) will do it, or do i need to Helicoil the thing to do it properly?

[heinkeljb]

As the bottom part is cast Iron and removable from rest of the carb, it should be easy to take off and get a good look down the hole.

Just remember that the bottom is a taper down to a small hole so when you wing the adjuster in it, it seal off on the tapper. If you go the route of using a tap, make sure it is one with a flat end so you don't damage the bottom tapper. Sorry, don't know what size / thread the thing is but it should be metric. You can buy thread gauges which have teeth on them which you match tot eh thread you are using and then look at what the thread gauges says it is.

I suppose as a last resort you could probably get a replacement block - maybe one of the European suppliers has new ones?

John