dibbons
Well-Known Member
I understand a choke pull off keeps the engine from running too rich at initial cold start-up. So I was wondering how a '65 carb without a choke pull off can do the same thing, or can it? Thank you.
How Does an older Carb without a Choke Pull Off Do It?
- Thread starter dibbons
- Start date
-
dibbons
Well-Known Member
OK, it's just the fast idle setting that keeps it going, forgot about that aspect.
Looking good. PS, they sell the plastic plug wire insulators. https://www.megapartsusa.com/proddetail.php?prod=101-PWBAX5
The purpose of the thermostatic choke spring is to close the choke butterfly when cold. Spring tension on the butterfly is "light". When the motor starts, airflow opens the butterfly slightly. This is not as precise an arrangement as a carb with a pull-off.
Yours clearly shows the choke pull off, but something is funky with the arm coming off the choke, it looks way too short.
dibbons
Well-Known Member
I found and reamed out 3 old insulators and one reproduction for the larger 8 mm wire. The reproduction does not snap in nice and tight to the valve cover bracket like the three factory originals.
The PCV is on the "wrong" side, but since I use it as kind of a wire separator, I'm going to keep that arrangement.
And when the choke thermostat coil heats up the choke butterfly comes open. There is no vacuum pull off so the choke coil in the intake and the air flowing past the choke butterfly open the choke. Disagree with me if you want but that's the way it works! Some of the Holley's have a small vacuum chamber that cracks the butterfly open as soon as the engine fires. I don't see that this carb does.
That is the primary choke pull, usually vacuum operated. Some carbs have vacuum operated primary and secondary choke pulls.
External. Hooked up with a vacuum hose. Most primary choke pulls get their vacuum directly from the carb. The secondary pulls often go through a thermal vacuum switch that is screed into the intake coolant passage. The thermal switches also provide a timed vacuum signal for the valve in the air cleaner snorkel.
65Val
Average Length Member
Should have a choke pull-off...
You're right. According to the parts catalog the 64's and 65's had a vacuum pull off.
dibbons
Well-Known Member
We have come full-circle, previous owner omitted factory vacuum choke-pull off. That would explain the plugged port on the back of the carb!
We all learned something today.
A learning experience!
Let's not turn this into a sale thread. Thanks (send him a PM instead)
-
