Idle Fluctuates

[69cudaownr]

My idle fluctuates between 700 and 800 rpm. What is happening? Is that some sort of vacuum leak?

 

[jbc426]

My idle fluctuates between 700 and 800 rpm. What is happening? Is that some sort of vacuum leak?

Describe your engine and carb set-up, and the guys should be able to guide you through some troubleshooting steps.

 

[69cudaownr]

Brand new Edelbrock Performer 1406 600 cfm carburetor on an Edelbrock Performer intake on a 318 with 302 heads and a mild cam upgrade. Its fluctuating while idling.

 

[Garrett Ellison]

What ignition do you have?

 

[512Stroker]

My idle fluctuates between 700 and 800 rpm. What is happening? Is that some sort of vacuum leak?

Check the PCV for vacuum leak
Pull it out and put your thumb over the open end while engine is at idle. Warning maybe HOT.
Idle mixture may be lean.

 

[furyus2]

Easiest test, is to put your hand over the carb, and see if it has any effect. If so, check for vacuum leaks. Carb cleaner should help. Also, make sure you set the timing before making any carb changes.
If all that checked out, turn the mixture screws in until the engine slows down, then back out to highest rpm/vacuum. Reset idle.

 

[69cudaownr]

What ignition do you have?

Stock distributor, not electronic.

 

[H22A4]

Do you have a vacuum gauge? If not consider borrowing or buying one. It’s almost as essential as a timing light when tuning an engine.