Carburetor Auto Choke Heater Tube

[Anonymous]

I have a problem (don't we all?) - I ordered a great carb from Pony Carbs and just sent my neglected autolite 1100 back. (1100 for an 1100). Anyway, my exhaust manifold had/has a crack right where the choke tube goes in but as result of the crack, someone welded the crack and the hole shut!

Therefore, I ordered a new choke tube (through pony carbs - about 2 feet in length) and it came with a clamp since I don't have a hole for the tube. Any recommendations on where or how I should mount the choke tube? In other words, does it need to just make contact with a solid source of heat or is there a special manner in which it should be clamped to the manifold. Perhaps I should just attempt to drill another hole somewhere else in the manifold?

What is common practice out there?Any help would be much appreciated, as always!

 

[MercuryMarc]

This worked for me when I had my 1 barrel 1940 carb:

No drilling required.

 

[CZLN6]

Howdy Marvista:

Do NOT drill into the manifold. The original choke hole is a tube that passes through the manifold and out/open to the bottom. Fresh air is drawn through the hole, heated and into the tube to the hot air choke. The hot air is drawn in, by a slight amount of vacuum, unless the throttle is opened while the choke is still operating. In that case, there is a vacuum pull off function to lessen choking.

All you need to do is to get the open end of the choke tube near a source of heat, like Marc's.

The downside of this system is that you are pulling unfiltered air directly into the carb on cold starts. All of these types of chokes/carbs are susceptible to internal crud and contamination. This is one reason why.

Putting the tube on top of the exhaust manifold and shrouding it, like Marc's solution, might be an improvement in intake air cleanliness, over the stock hole exiting out the bottom of the exhaust manifold. Ideally, it would be best to provide a filtered air source to the hot air tube intake.

You might also cover the tube for two reason- to insulate and retain heat better, and to keep from accidently burning yourself from touching the tube. Many OEM applications have a woven material, tubing that slips over the hot air tube.

Adios, David

 

[ludwig]

I used the tube and collector like Mark has; it came with a heatproof fabric jacket. I got it at a speed shop. Some guys use a length of 1/4" soft copper or aluminum tubing and wind it around the manifold for a 3 or 4 turns.
Taking Bhodi David's remarks one step further, you might get an extra long tube, do the winding and leave a length sticking out so you can clamp some sort of filter ball on the end, away from the heat source.

 

[wallaka]

You might not even need it. In Alabama I don't need a choke. Don't know the climate in CA but if it's mild you don't need one. Just pump the gas before you turn the key.

 

[Anonymous]

great ideas...I ended up running the tube along the exhaust manifold and now i'm looking for a piece of scrap metal i can use to shield the tube to the manifold....this should do the trick. I've also notcied that my car is taking a while to heat up, or at least the choke is. I decided to run my heater hose through the bracket that is mounted on/behind the black auto choke housing...this made a huge difference! I'm still not completely un-choked until about 15-20 minutes of driving, but i'm convinced it's because the carb "thinks" i need to be choked longer...until next time...thanks for the input!

Oh and one more item, I haven't even adjusted my timing or the idle screws yet and I can already feel a difference in carbs - So far, I would recommend Pony Carbs for anyone that wants a quality rebuild...I say this after I rebuilt my last one, but still didn't feel it was enough.