Frozen choke??!!

Does anyone have a the hot air choke system in operation that they used at least in the 72-75 years. I have a 74 258 with this system. Mine is simply a piece of fuel tubing going from the exhaust manifold to the choke housing. It works however the last few times I've gone to start it the choke has been frozen open. I noticed that there was some condensation in the choke housing last time I took the cover off. Question is does anyone know how to stop moisture from getting in there?

 

I had the same issue, so I installed a manual choke. Eventually I replaced the carb with a Weber. Supposedly, the choke linkage has a special coating to prevent rusting and corrosion that wears off after time.

 

I still have the original choke stove on my 75 w/258. It is attached via a copper fitting to the choke housing and then does a 180 back to the exhaust manifold. This baby get HOT after start-up and then the bi-metallic spring in the choke housing loosens up to allow the RPMs to drop and the choke to open fully.

There is also a fitting UNDER the exhaust manifold that routes a hose that plugs back into the Carter YF. I tried fuel line with a hose clamp but it kept coming off and I did not like that set-up. Last week I fashioned a two foot long section of copper tubing to accomplish this and it seems to be the answer. Don't know if its really required but this morning it was in the low forties here in the Atlanta area and she fired up perfectly with the climatic choke. Once warmed up a slight touch to the throttle dropped the RPM's down to 700.........Perfect !!!

Let me know if you need pictures........

Don't know how moisture could accumulate, unless the Jeep has been sitting for a long while. The choke tube is actually covered with an asbestos sleeve cause it gets so hot and I'm sure ANY moisture would dissipate.........

 

I think the moisture is just moisture from the exhaust (you know how you see drops come out of exaust pipes sometimes). I think I am going to try and work out some kind of collector system. I have a question though, on the coldest day how long does it take before your idle drops down to curb idle.

 

Can anyone else help on this?? Do I need a new carb??

 

A couple comments...

The "climatic" or thermoelectric choke has only one element that opens the flap - the bimetal coil that unwinds as it heats up. There are three sources of heat though. The first is the electric current that flows through the coil when the key is on. This heats the coil by resistance, and it will heat up more the longer the key is on, until it reaches an equilibrium temperature where the radiation of heat from the coil equals the resistive heating.

The choke stove sends heated air into the black plastic cylinder (cover) that surrounds the coil. This both heats up the coil due to the warming of the incoming air by the manifold, and raises the equilibrium temperature for the resistive heating. The flow of air works by manifold vacuum, conducted from the carb base to the cover. There needs to be vacuum, and there needs to be no leaks from the cover to the air inlet in the heated pocket in the manifold. If this tube is broken, you can get a "Help" kit that will replace it.

There's also the heat riser flap between the mainifolds. This flap directs hot exhaust gases against the base of the intake manifold when the engine is cold. It needs to move freely, and the spring needs to hold it in the open position when the engine is cold. This more affects the atomization fo the fuel in the intake manifold, but also warms up the carburetor.

All these need to work, especially the first two, for the choke to open properly. Additionally, the fast idle cam and linkage needs to be clean so that the carb won't stick in fast idle.

BTW that asbestos around the choke stove tube is there to keep the heated air from cooling off (in very cold weather) before it gets to the carburetor.

 

I do not have that asbestos covering. I wonder if that is my problem. Lack of that cover would make the heated air turn into droplets wouldn't it?

 

Possible... you can't get asbestos now, but I believe the plumbing supply sells fiberglass tape to insulate steam pipes. You could try that, and hold it on with some wire. I'd also make sure you have no leaks in the tube, that the tube is clear, and that there's vacuum at where the tube attaches.

The electrical part has to work too. Sometimes the bimetal spring fails.

 

The Help kit I have seen has some sort of covering included (looks like asbestos) what electrical part are you referring to? I do not have any electrical componants. Are you positive of an electrical part on a 74? The main issue I have is that water is getting into the choke housing and the choke freezes overnight and will not close the next morning. Also it does high idle a long time before it drops down (like 15+ minutes).

 

timgr

maybe I'm missing something, but I do not have an electrical wire running to my Carter YF. As far as I know, the climatic choke works only with heated air relaxing the choke spring. Please corrct me if I am wrong.

I know that for '75's YF's are available that have either the climatic or electric choke.....not sure about '74.

 

No, not positive. Ok, looked at my manual and the YF choke (for '77) is thermostatic, not thermoelectric. No electical connection.

Never mind.