2100 carb connection help

[rd100]

I'm new to this on my inherited F100. My truck was having a hesitation and then started having a problem holding idle, I replaced the sparkplugs/wires and it was still there, I'll eventually get to the points etc. I wanted to rebuild the carb.

I've taken the Autolite 2100 carb off to rebuild it.

While in the process I noticed that the two lines that connect from the carb to the passenger side rear cylinder exhaust manifold weren't connected down there at all, they were both just sort of free floating around the holes.

What is that connection, something to do with warm air intake/exhaust to the carb/choke?

What does the connection at the manifold look like? I'm guessing the manifold must be too far gone as I don't even see where it would fasten, there's just two small holes on that part.

Thanks

[72bumbee]

I believe it is a vaccume line. and a larger hose goes to the valve cover grommit for a pcv valve. If someone else doesn't post a pic, I can dig out my pics from mt intake gasket replacement.

[craftsman]

Yes, that is the heat riser to the choke. I think it does pull a slight vacume, they should push down in the holes but probalbly rusted off. Holes are just rusted shut, you may be able to dig it out, or maybe drill them out.

[72bumbee]

I found my pictures. If this block (circled) is what is in question, then what I have hooked to it, is a rubber line (small) going to the transmission (i think) and the larger line goes to the power brake unit. there is another nipple on the block (circled) that has a rubber cap on it as a blank I suppose? I didn't have anything going from that block to the old autolite!
Hope the pic helps anyway.
Steve

DSC06282.JPG

DSC06282.JPG

[rd100]

It's not by the valve covers, it's way down on the passenger side, on the rear port of the exhaust manifold.

The tubes were just sort of butted up against the holes in the exhaust manifold. So is that how it's supposed to be? Is there no actual screw down connection method?

[72bumbee]

got me stumped!
sounds like a modification.

[george worley]

What Craftsman said is correct, it sounds like your choke tubes have just rusted off at the ex. manifold. You can get replacement tubes, push the old one over a little bit and you should see the holes in the manifold. Clean out ther holes, the tubes just push down in the holes.

[fordman]

like craftsman said those 2 tubes are for the choke heat activation. those tubes supply heat up to the choke and make it operate correctly when the truck is running. if the tubes are rusted off you can drill out the rusted out part and reinsert new tubes.

[rd100]

Thanks guys, where would be a good place to find replacement tubes?

I do see the holes in the ex. manifold so I know where it goes I just couldn't figure out how it was held in place since as I now know the insert parts must still be in the manifold and the tubes just have the flange left on them.

Would that be one possible cause of why my truck wouldn't hold an idle and also a stumbling when revving the engine up or down?