Hole in top of 2100 Autolite; what goes in it?

[danno 128]

I have a iddy biddy Autolite 2100 on my 302, and it has a hole in the top cover over the float bowl. I have a spare carb, and it has the same hole.  It must be a vent?  What is supposed to go in this hole to plug it?  There must be a valve or something?

[lanky 44]

If I'm thinking of what you're thinking of, there's is a hole that's supposed to be plugged by a little armature that moves a plug type thing for venting gaseous fumes. I just searched for images, and to my surprise most 2100s seemingly don't have what mine has (neither armature or the hole) . I once did some reading up on them, and there were quite a few variations over the years. Including cfm differences and small part differences.

[lanky 44]

I can photograph tomorrow if you would like btw

[danno 128]

I am thinking something used to be plugging the hole, and now it is gone. I bet I could fill it with some gas resistant gasket sealer, and maybe put  a pin hole in it for a vent?   I wonder if a vent is even needed?

[Max Power 74]

Guessing you mean something like this:

 

 

Not completely sure why some applications had it and some didn't, but whenever there was a hole, it was covered but not sealed. I believe it was actuated by the same assembly as the fuel pump, I am not sure why.

 

I would feel weird about leaving it open. I have heard of people plunking a loose bolt in there, preventing most debris from getting in but not air sealing it, as they had the vent there for a reason.

[Rsanter 152]

Early models had the arm with the rubber thing to block it. Later ones did not have anything.

Just leave it as is, it doesn't take anything.

 

Bob

[danno 128]

Ok, I think I am missing the rubber thing.  That was my guess. I like the idea of a lose screw in it, with just a big enough gap to allow a vent.

Thanks

[Ridge Runner 1,113]

On the earlier carbs this hole is open .The gasket for the top has a small hole right under the top plate hole .It is a vent for the front bowl .later carbs had the arm with the rubber  plug .i can/t remember what year they added the arm but it was 71 -73 i think .My old 73 Mach 1 had the arm and rubber plug .

[Ridge Runner 1,113]

If you plug it i dont think the front bowl will vent 

[danno 128]

I will put a slightly loose screw in it, with a self locking nut so it won't back off.  That way it can vent if it needs to, which will never be much.  

 

Thanks for the photos and ideas. I will see if the little rubber piece might have fallen off on my bench.