The Stovebolt Site Forums The Shop Area Engine Shop Rochester Carb Vent Hole?

First off, the truck is a 1954 Chevy 3800 with a 235 and a Rochester B Series carburetor. I just rebuilt the carb and after many hours of swearing and cursing the previous rebuilder, it's all back together. Long story short, the big ball went in the float ball instead of the aluminum one and it took way too many hours to undo the previous rebuilders mess. Back to the question, when it all went back together I realized there was a hole in the top section of the carb right by the choke lever. I went through my pictures and it was always there. For anyone that knows, is there supposed to be a hole for a vent or something? I read the Monojet's had vent holes in them. All the pictures I found online don't have the hole in the side, which concerns me.

Thanks for the help,
Joe

I went out and looked at 2 old Roch B's I have in my stash. On the choke lever side above the cast in ID info there is a plugged port on both. This port I'm talking about is just above the ID casting just below the choke lever on the upper side . Is this the area you're asking about?

If so you should be able to plug it.

I'm asking about on the side of the carburetor. Like if the carb was mounted to the engine and you looked at it from the drivers side of the truck, there's that nice flat rectangular area. It's right above the back screw that holds the two halves together. I think I'm just going to try to find a rubber plug to stick in it.

Joe

None of the 3 Roch B's I have (2 in parts stash, 1 installed on a 216) have a hole anywhere on the drivers side of the housings and the area you descrobed is smooth with no hole.
All of mine are manual choke versions, I'm unsure about the automatic choke.

One of the B's in my stash came off of a 54 235, course the odd's it was the original are pretty slim.

Joe - Can you get a pic of the hole you are referring to in your description?

https://www.dropbox.com/sh/dyk1our20dzf5qs/AAC8EDbC9peninbF0WArZvuFa?dl=0

There's a link to all the pictures I have. You can see the hole in the side of the carb before and after I rebuilt it, as well as when it was still on the truck before I bought it. There's no flashing inside like if someone drilled a hole in it.

Oh, the two holes in the bottom of the float bowl are my doing. The previous rebuilder forced the big steel checkball into the hole and no amount of heating, taping, and scraping would get it out.

Joe

Theres no hint of a hole in that location on my 3 Roch B's. Do a temp plug and test, May have been a reason for it.

Yes, it's a vent hole.

Helps prevent...rough idling, stalling & hard starting when hot,

caused by extreme temperatures vaporizing fuel in the bowl
and pushing it into the carb throat.

To correct, drill a hole....

Would you look at that, thanks Oilrag. I showed one of the guys up at work this morning and he said it might be either a vent for that or to let air into the carb with the choke closed. Either way, I'm just glad I know why it's there. Thanks for all the help.

Joe

Wow, learn something everyday.