Carb Tuning Question

[stirling33]

I am having what I assume to be some carb issues. Lately it will stumble when wide open then also surge while just cruising.

It does not happen everytime I run the car but often enough where I guessing something needs to be adjusted.

Is this a Jetting issue or what else could it be - I am running a standard 4160 Holley 600.

 

[mrmustangman357]

check to make sure your timing is right, fuel pressure is good, and floats are adjusted first. after that pull the pugs and see how they look

 

[jcode68]

check to make sure your timing is right, fuel pressure is good, and floats are adjusted first. after that pull the pugs and see how they look

+1 on all of this and will just add that I had same symptoms even after the above was checked out. My plugs showed I was lean (were very light, some were white). I have a Holley Street Avenger 67 cfm. I increased my jet size by 4 increments and it is running really well now. The surging is gone and throttle response is great. Cheap and easy fix, but took a while to determine this was my problem.

 

[stirling33]

+1 on all of this and will just add that I had same symptoms even after the above was checked out. My plugs showed I was lean (were very light, some were white). I have a Holley Street Avenger 67 cfm. I increased my jet size by 4 increments and it is running really well now. The surging is gone and throttle response is great. Cheap and easy fix, but took a while to determine this was my problem.

Thanks will look into all this tonight....

 

[woodsnake]

From here it sounds like ignition, check the wires around the distributor and coil for frayed ends, cracks, etc...

 

[RGS0907]

I am having what I assume to be some carb issues. Lately it will stumble when wide open then also surge while just cruising.

It does not happen everytime I run the car but often enough where I guessing something needs to be adjusted.

Is this a Jetting issue or what else could it be - I am running a standard 4160 Holley 600.

It's nearly always ignition. I wouldn't do anything to the carb until you fully check out your ignition. Get a vacuum guage & see what it reads. it should be at least 18.5" with a steady needle at 800rpm. If the needle fluctuates a little, it means that your timing is retarded. I did the same thing last night & pushed my timing to get 20" of vacuum & the car ran fantastic after that.

 

[D.Hearne]

Also check the fuel filter, a clogged filter will also cause this. You ARE running a filter, right?

 

[stirling33]

Also check the fuel filter, a clogged filter will also cause this. You ARE running a filter, right?

I am running one - I will check that as well, thanks guys.