85 2.8L carburetor issue and also a radio issue

[JoeDaddy21]

The electric choke was usually powered by alternator so choke spring would only Warm UP when engine was actually running

If it was powered by Key ON voltage then driver may turn on the key and NOT start the engine right away, for ??? reason
Then when he did start engine choke would be open too far and wouldn't run well until engine actually warmed up

There was never a good "automatic" choke setup on a carburetor, you would ALWAYS need to adjust them for winter and then summer temps.
Manual chokes work the best

So I tested it with the engine running, and it never opened. Even with the direct connection it didn’t open. So does this mean I have an issue with the automatic choke and not the wire? It runs fine, but I feel like it may run better if the choke opened up all the way

 

[RonD]

Yes, something is wrong with choke spring or its heater

Choke plate is there to increase flow from the Jets when engine is cold, to make a Richer air:fuel mix




Liquid gasoline CAN NOT be ignited by a spark, yes the movie guys take liberties with that one, lol
ONLY gasoline VAPOR will ignite with a spark
COLD gasoline has very little vapor(you can't smell it, you smell the vapor) not the liquid gasoline
To start an engine you need at least 30% vapor in a cylinder for it to fire completely, vaporizing the rest of the gasoline.
Now compression is HEAT so as engine cranks it will warm up cylinders, and of course once engine starts the cylinders warm up pretty FAST

But to get it started you need that 30% vapor, and thats where the choke plate comes in
Normally Jets are set to run engine at 14.7:1 air: gasoline ratio
If gasoline coming out of the Jets is cold and say 15% vapor then you would need twice as much gasoline to get the 30%
Choke plate restricts the air coming into carb ABOVE the Jets, but engine still generates the same vacuum, cranking or running, so more gasoline is sucked in from the Jets because less air is available
So engine can start
Once started choke should open a bit because cylinders get HOT pretty fast, but gasoline in carb is still cold, so too avoid stumbling you still need a "richer" mix.
As engine bay and intake warm up so does the gasoline in the float bowl and fuel line feeding the carb
So more vapor available and no more choke needed

Fuel injection computers do the same thing, they "choke" a cold engine, but in this case its just a Richer mix to get the 30% vapor and the higher idle

 

[JoeDaddy21]

Yes, something is wrong with choke spring or its heater

Choke plate is there to increase flow from the Jets when engine is cold, to make a Richer air:fuel mix




Liquid gasoline CAN NOT be ignited by a spark, yes the movie guys take liberties with that one, lol
ONLY gasoline VAPOR will ignite with a spark
COLD gasoline has very little vapor(you can't smell it, you smell the vapor) not the liquid gasoline
To start an engine you need at least 30% vapor in a cylinder for it to fire completely, vaporizing the rest of the gasoline.
Now compression is HEAT so as engine cranks it will warm up cylinders, and of course once engine starts the cylinders warm up pretty FAST

But to get it started you need that 30% vapor, and thats where the choke plate comes in
Normally Jets are set to run engine at 14.7:1 air: gasoline ratio
If gasoline coming out of the Jets is cold and say 15% vapor then you would need twice as much gasoline to get the 30%
Choke plate restricts the air coming into carb ABOVE the Jets, but engine still generates the same vacuum, cranking or running, so more gasoline is sucked in from the Jets because less air is available
So engine can start
Once started choke should open a bit because cylinders get HOT pretty fast, but gasoline in carb is still cold, so too avoid stumbling you still need a "richer" mix.
As engine bay and intake warm up so does the gasoline in the float bowl and fuel line feeding the carb
So more vapor available and no more choke needed

Fuel injection computers do the same thing, they "choke" a cold engine, but in this case its just a Richer mix to get the 30% vapor and the higher idle

Thank you for your detailed description of carburetors. So I should get a new choke thermostat with the spring and see if that fixes it?
Also, what does the pull off on the back do?

 

[RonD]

There is a choke spring, I guess it could be called the thermostat(most call it that, lol), you adjust it for current outside temp winter or summer
So when cold if closes choke plate just enough for cold start
Then allows it to open a bit on start up
as the spring warms up it expands which makes it uncoil opening choke all the way

Good page here on the 2150 choke: http://grantorinosport.org/bubbaf250/carb/carb02a.html