MTFCA Forum

Looks like the gasket will seal off the passage, so is there any compelling reason to plug the hole?

That passage is the key to the idle system working. Further Henry wouldn’t have spent the money if they didn’t think it was needed.

Les, was Henry really spending the money? buying the carbies in at a set contract price would make no difference to him if plugged or not.

I have always figured that hole was a manufacturing passage drill path, and that end of it needs to be plugged to operate properly? But why pay good pennies to have someone plug the hole in the factory when the gasket will do it for free?

Then, on the other hand, why not plug it?

Whether it gets plugged or not, I would pass a file over the face of the flange to clean it up and insure that it's flat. With what looks like some fair pitting between the plug hole and the throat, I might be concerned with a leak path, were the hole left unplugged.

Let me be clear about this, the hole had a brass plug that I removed along with the other two. Of course the other two had to be repluged after the passages were cleaned. But,I’m thinking the gasket will seal the passage just fine??

Why plug the hole? I've asked myself the same question... once. My answer was "to finish the job correctly and completely". I can make and install a brass plug faster than you can tap the hole and stuff a screw into it, and when the job is for a customer, they are receiving a carb that is done correctly, completely, and will function exactly as designed with no risk of some random booger falling into the hole and causing a perplexing problem for the next 2 years or until the carb is thrown away and my reputation is trashed along with it.

For yourself, go for it. It will run fine so long as you use a modern soft paper gasket. If you use an original brass-clad asbestos seal there would be some risk of (probably undetectable) leak due to the pitting on the face of the flange.

The hole is too close to the carburetor bore to expect a gasket to seal it. Exactly why was the passage drilled? Is it certain that it needs to be plugged for all applications?

The passage is where fuel flows from the bowl to the back side of the butterfly. It provides fuel at idle. There is a good diagram of passages on modeltfordfix if you want to see it. I used a piece of a brass screw to plug the hole. It was easy to do. I've also used threaded plugs (set screws).

I'd plug it securely with a plug similar to other plugs in the carburetor body, then file it flat with the gasket surface. It looks to me like it's too close to the main bore to tap. I'd use a lead or soft brass plug.

Thanks for the input. I was going through a corner of the shop and found a 5 gallon bucket of NH bodies, my Dad and I gathered up in the early 60’s. They still had the wire my Dad tied on them to hang them on the shop wall, this just about melted my heart. Anyway, Two of the bodies have brass plugs in the top and bowl area but not the gasket area. Back in the day we didn’t know anything removing the plugs and cleaning the passage ways, so if a old mechanic did remove the plug —-you get my drift. That’s the origin of the question. I use the tap and threaded stainless plugs to make it easier for the next guy. Anyway thanks for all the responses.

A "popular" rebuilder told me he uses brass eschutcheon pins. Pounds them in, and files them flush. That's what I used. Works great.