I noticed when poking around the engine bay of my 84 f150 4.9L this metal tube that is connected at one end to a hose on the carb was disconnected. Where does the other end of this metal tub go to?

 

I'd say its the cold air line for the choke stat and should attach to the exhaust manifold. These lines often rust and break off where they attach to the manifold.

 

Look at the exhaust manifold near the #5 cylinder. The part in the photo was likely attached to the top of the exhaust manifold and then attached to a port near the top of the carburetor. Originally, the rubber tube was red in color.

On the bottom of the exhaust manifold [opposite the top tube] is another metal tube which goes to the choke housing. This tubing should have a light colored [white] insulating sheath.

The purpose of this system is to provide heat to the choke bimetallic spring which parallels the warm-up cycle of the engine. On the 1984, there also will be an electrical wire going to the choke housing. There is an electrical heater inside with the bimetallic spring which receives it current from the "S" stator on the alternator. Clean filtered air is provided through the port at the top of the carburetor and is drawn to the choke by a small vacuum port inside the choke housing. This air is heated by passing through a tube in the exhaust manifold. The air does not mix with the exhaust gasses. With the tubing disconnected, as yours is, non filtered air is being drawn into the choke and mixing with the incoming charge.

It is not uncommon for these tubes to rust through... after all, your truck is almost 30 years old!

There are repair kits available in the "HELP" section of most parts houses for less than $15. It will be listed as something like choke heater tubing repair kits. Talk with someone older than 50, behind the counter. Many younger employees do not know what a carburetor is, much less how to repair a choke!

Good luck!

 

Actually, that is the inlet tube and went to the bottom originally. The heat tube comes off the top of the runner. Same information on the repair applies, except the bottom is easier to get to, and I would just drill it to 1/4" and use a piece of 14" steel tubing for a replacement.

 

Dorman® Help!® 76850 - Choke Heater Tube Kit | O'Reilly Auto Parts

Seems like this aught to do the trick. RIght? I think in truth a lot of the young guys like me (21) like carbys for some reason .

 

Yes, that will do just fine. You're young enough that carburetors were no longer installed on anything built here when you were born. It was like my son when he had his Corvair, breaker points had long gone away by the time he started driving (1993).

 

I will say that I DO NOT like working on breaker points ignition. Real PITA on the 73' Honda CB350 motorcycle I used to have.

 

At least on the Corvair, the distributor was easy to get to, open the engine lid (rear engined) and it was right there on the right side of the fan belt idler.

 

Watching "CORVAIRWILD" on youtube I have mixed feeling on Corvairs, the later ones sure look purty

 

His was a 1965 Corsa with the 140 hp 4 carb engine. It had been bored .030 over and had a hotter cam. It was probably around 170 hp.