Factory style choke problems

[Guest rbarnett614]

I have worked to get the heat riser and choke actuator to work correctly on my '65 with a 401. The problem is that when I replaced the exhaust, the shop removed the heat riser butterfly valve (it was broken anyway) because the car had an electric choke at the time. Now that I am going back to a factory-style set up, does anyone know where I can get the correct butterfly valve assembly? I've never seen on that actually works and don't know if it uses a spring or a weight - or a combnation of both. Any help you can provide is appreciated.

[Jim Cannon]

I am not a '65 Riv expert. But on a '63 the butterfly that you have removed does not really impact how well or quickly the automatic choke warms up. The thermostatic coil gets warm because the carb draws hot air into the little black housing due, to a vacuum port in the carb.

If your coil is not getting warm, make sure that little port is open and is drawing a vacuum. The vacuum also pulls the little piston inside the black housing back, to open the choke a bit when the engine starts.

The hot air comes up through a steel tube that connects to a tube that goes through the exhaust manifold. It is not supposed to draw exhaust gas into the coil housing, just hot air (but when there is an exhaust leak in the tube through the manifold, it does).

The missing butterfly helps with cold weather driveability, helps warm the intake manifold up when first starting out, and warms the base of the carb. Be sure to use the stainless steel plate and a normal gasket, per the shop manual, to protect the carb base. I don't know where you are located, so I don't know how cold it gets there, therefore if you need the butterfly or not.

I hope this helps.

Edited September 19, 2011 by Jim_Cannon (see edit history)

[RivNut]

There were two styles of passenger side exhaust manifolds. One style had the butterfly built into it and the other style was shorter and the butterfly was bolted to the end of it. If you're SOL and really need the butterfly (meaning, as Jim indicates) you live in the North and you'll be using the car as daily transportation you could find a manifold that has the bolt on butterfly and swap them out.

[Guest rbarnett614]

Thanks for both of your replies. They both give me some great information. My exhaust manifold is the shorter type with a bolt-on butterfly valve.

I really don't need a butterfly valvle due to the weather where I live. I live in Ft. Worth, TX. But since I've worked to get the rest of the setup factory correct, I would like to replace the valve.

I checked and there is vacuum coming from the carburator port and the chocke opens slightly when the engine starts. The main problem is that the choke will not close enough to set the fast idle circuit = and I've worked to make sure that is set right. I may not be getting enough vacuum from the carb to keep the choke where it needs to be until the car is warm. I've even completely rebuilt the black choke vacuum can that operates the choke butterfly and puts the car in the fast idle circuit.

But I'm ffinding that the car slips out of fast idle and the choke opens before the car is warm. Also it will occassionally go into fast idle once the car is warm.