Surging

[RustBuket]

I have a freshly rebuilt 305 in my blazer and it is having carb problems. Its all stock except for headers, dual exhaust, and a edelbrock performer intake. The truck seems to surge at idle. The rpm will not stay constant. I think this is symptoms of a rich mixture because the truck runs very cool and you can smell gas as you drive with the window open. How can I adjust this? Do I need a vaccuum gauge?

 

[RustBuket]

Nobody?

 

[Twiz]

I'd say your on the right track.

Surging is a common symtom of a rich mix.
Assuming everything else is stock (including the carb), except for a free-slowing exhuast/intake. The engine can breath better, then the stock carb was calibrated for.
Richening the jets, and changing the meetering rods, may correct the problem.

Make one small change at a time, drive it, and change again as needed.

 

[RustBuket]

So you think I should richen it even more? Would adjusting the idle mixture help?

 

[Twiz]

Opps....

I think it needs to be leaned out.
I'm not sure what the hell I was thinking on that other reply. Made sence at the time.. /forums/images/graemlins/grin.gif

 

[RustBuket]

Ok, well I'll see what I can do.