The Stovebolt Site Forums The Shop Area Engine Shop Carb overhaul

The Carter YF 964S (was on my '52 GMC when I bought it 13+) years ago started having problems about 6 months ago. When it sat over night the float bowl would drain down, which meant I had to crank the engine over a bunch before it would start. Also, the mileage dropped from about 13 MPG to around 6.

I removed the Carter and installed a Zenith 28 (which was the proper type for my 228, but not the exact model) that I had. It ran okay, but not near as good as the Carter.

I bought a kit for the YF and installed it last week. Truck seems to be running fine, although idling a bit high. I filled the gas tank this morning and will report MPG results after the next fill up.

BUT ....

Two of the 10-28 screws (see picture) that hold the top feel like they want to strip out the threads in the body of the carb. They are still holding somewhat and the carb doesn't appear to be leaking. The only "fix" I can think of would be to drill and tap the two blind holes in the body to #12 size machine screws.

QUESTIONS:

Anyone have a better idea?

If #12 screws are the answer, should I use 12-24 or 12-28.

Maybe just a drop of green Locktite on the threads. It's not the correct fix but if it's not leaking at the moment. I would do each screw one at a time, so as not to lose the gasket seal.

I'm pretty sure I have some 10-32 helicoils in my box of stuff, which is what I'd use. 10-28 is an uncommon thread pitch, so I'd confirm what you have first. If you do drill for #12 screws, match the pitch to what the #10's are (10-32 fine or 10-24 coarse).
The #12 screw heads would look weird, being bigger.

I don't know "green" loctite Craig, but I'll look it up.

Kevin, I had 28 tpi on the brain while thinking about the #12 screws. The current screws are 10-32 (I think). I didn't realize they made helicoils that small. How big do you have to drill the hole in the carb for the helicoil? There isn't a lot of meat available.

Get some longer screws and see if they run all the way through into some remaining good threads. If you feel any resistance, stop and remove the long screw and run a tap all the way through.
This has worked for me in the past.

Basically to install a helicoil, the drill size is the same as the major diameter of the size you're installing. So you're not really taking out that much metal. I have just run the helicoil tap through a part with fully stripped threads without drilling. The set I have is 10-24 and needs a 13/64 drill. Drill size for a 10-32 helicoil would be the same. It looks like you can get a 10-32 helicoil type thread repair kit for under $30 on Amazon. Actual Helicoil brand is crazy expensive now.