1 brl carb 250 motor how to adjust

[chevyn0va1]

does anyone know how to adjust a carb on a 250 74 nova? This is a non a/c non emissions car but it has the idle stop solinoid on it.

[AlmostStock]

Rebuild kits for your carb are less than $20 and come with instructions on how to set everything. The idle stop solenoid should be adjusted so that when you unplug it the engine drops down 100 rpm from the normal setting.

[chevyn0va1]

Originally Posted by AlmostStock

Rebuild kits for your carb are less than $20 and come with instructions on how to set everything. The idle stop solenoid should be adjusted so that when you unplug it the engine drops down 100 rpm from the normal setting.

I have a new rebuilt carb so i dont need to rebuild it. The idle stop was disconnected because it was making the car's throttle stick. once unplugged it never happend anymore but now the car idle low and rough at a stop light. any Idea how to adjust?

[AlmostStock]

Originally Posted by chevyn0va1

I have a new rebuilt carb so i dont need to rebuild it. The idle stop was disconnected because it was making the car's throttle stick. once unplugged it never happend anymore but now the car idle low and rough at a stop light. any Idea how to adjust?

Did you ever adjust the idle mixture screw? It's in the base of the carb and has a spring on it. The best way to set is with a vacuum gauge connected to your intake manifold. But a tachometer will also work or even your ears. First, with the engine off, turn the screw all the way in (gently) and then out two turns. Start it up and slowly turn it back in while watching the gauge. When it goes down stop and slowly back the screw out. You want highest vacuum or rpm's.

Now set your idle speed. If it's an auto then it should be about 600 rpm in drive with the parking brake on and wheels blocked. The solenoid is adjusted be turning the bolt that contacts the throttle arm. It should idle on the solenoid (at 600) when plugged in and then about 100 rpm's lower on the carb stop screw when unplugged.

[chevyn0va1]

Originally Posted by AlmostStock

Did you ever adjust the idle mixture screw? It's in the base of the carb and has a spring on it. The best way to set is with a vacuum gauge connected to your intake manifold. But a tachometer will also work or even your ears. First, with the engine off, turn the screw all the way in (gently) and then out two turns. Start it up and slowly turn it back in while watching the gauge. When it goes down stop and slowly back the screw out. You want highest vacuum or rpm's.

Now set your idle speed. If it's an auto then it should be about 600 rpm in drive with the parking brake on and wheels blocked. The solenoid is adjusted be turning the bolt that contacts the throttle arm. It should idle on the solenoid (at 600) when plugged in and then about 100 rpm's lower on the carb stop screw when unplugged.

ok ill look into doing that. Do you know how i can test the soliniod to see if it is even working? How do I connect a vaccum gauge to the intake (via the pcv valve?)?

btw yes I have an automatic.

[AlmostStock]

To test the solenoid turn the ignition on (the engine doesn't need to be running) and unplug and plug in the wire running to it. It should snap out when energized. You can hold your finger on the end of the bolt that sticks out and contacts the throttle arm and feel it.
As far as where to hook up the vacuum gauge I don't remember the easiest location on the 6 without looking, but any where on the intake or low on the carb would be ok as long as that point always shows a reading when the engine is running. You don't want ported vacuum which will read zero at idle.
Let us know how it turns out.

[chevyn0va1]

Originally Posted by AlmostStock

To test the solenoid turn the ignition on (the engine doesn't need to be running) and unplug and plug in the wire running to it. It should snap out when energized. You can hold your finger on the end of the bolt that sticks out and contacts the throttle arm and feel it.
As far as where to hook up the vacuum gauge I don't remember the easiest location on the 6 without looking, but any where on the intake or low on the carb would be ok as long as that point always shows a reading when the engine is running. You don't want ported vacuum which will read zero at idle.
Let us know how it turns out.

ok ill check my solenoid they way you said i tried pluging it back in but didnt see any movement but will try my ffinger on it while i clip it back on and off

[ALMB~Nova]

I found a 4 barrel intake for mine, should make for interesting bench talk