Hey guys, my car is having problems idling and also with just normal driving. I have a couple of questions for those of you who know things about carbs.

First it is really rough idling even when it is not cold outside it takes a hot minute to get the car to be able to idle without giving it any throttle.

And secondly, when driving if I stop at a stoplight and then go to accelerate it bogs down and dies. This also happens when I am driving around 20 mph and I cruise without giving any throttle. Once I give it the throttle it tries to die and the rpms plummet to around like 200. Not sure exactly what to do in either of these situations

Thanks

 

First question, what and trim level and year is the car and does the car have any modifications? Is the rats nest intact? Have you checked for vacuum leaks? The first step is checking for a vacuum leak and ensuring the ignition and fuel systems are operating normally and are using good quality components.

How long have you owned the car and was the car sitting for some time? Has the carb ever been apart? Is the fuel filter clean?
I'm concerned about sediment in the tank plugging the fuel filter and sediment in the float bowls. It can sometimes be difficult to get the engine to idle without throttle when its cold. Are you using the choke when the engine is cold?

Any recent part replacements?

 

Okay, so new parts include the exhaust, I put on the Headers and Presilencer from Racing Beat. That is when all of these things started happening by the way. I haven't let the car sit for a while after I got it. The rats nest is intact, and the fuel filter is recently replaced.

 

you should probably check for vacuum leaks first.

i don't remember my car having those issues when i first put my header on it, but that was also 30+ years ago, so .... at any rate, i did have to adjust the carburetor some. just find the idle mixture screw and follow the procedure. however, like i said, make sure you don't have any vacuum leaks first though.

 

Did you have Racing Beat headers? If so did you put gasket maker or some sort of gasket on the air control valve block off plate? That might cause a vacuum leak. Also how many turns should the air/fuel mix screw be? Is there only one screw on the stock carb because I thought there was two but I can only seem to find one.

 

on my 12A engines i ran a Rotary Engineering header.

for the ACV block off, i've run both gasket and silicone - not at the same time though.

the idle mixture screw will be accessed from the driver's side of the Nikki. it will be pretty much dead center at the base of the carburetor. the idle speed screw will be off the right of it. Section 4A of the FSM covers how to adjust it. make small adjustments at a time, then check to see if the car likes it or not. when you get it to where you like it, then set the idle speed.

 

From the factory the idle mixture screw has a metal cap over it to prevent tampering, you have to cut it off to access and adjust the mixture screw.

 

Hello I am sorry to hear this i wanted to ask if your carb is fixed yet