need basic advice on adjusting 68 Camaro Edelbrock carb

The screws you descibe are for idle adjustment, they will have no effect at higher RPM. You need to change main jets and/or metering rods. Metering rods may do it, and they are accessable from small covers in the top of the carb. Greg

Greg, ok, I think I remember doing that a long time ago, my only experience with carbs is the old Rochester Quadrajets. But how do I know if it's running too rich or too lean? Should I try various settings, trial and error, or just take it to a mechcanic to have it fine tuned? I'd rather work on this car myself than pay a garage-- thanks for your help, Terry

I just took the Camaro out for a drive on the highway, it misses pretty bad over 55 mph, maybe it is running too lean. I'll have to check the timing too. I just purchased this car a couple weeks ago, so I haven't done much besides put in a new set of spark plugs.

-- Terry M.

Take a look at your spark plugs. If the insulators on the tips are yellow and glazed looking, then you are lean. If they are black and sooty, too rich. white to light tan is just right. - Gary

OK I'll let 'er cool down and then pull a spark plug.....

OK, I pulled a spark plug, it has very light grey coating. Looks pretty normal to me, definitely not too rich. There's a little engine oil on the spark plug threads too, but none on the exterior of the head-- is it a sign of trouble? I'm no engine mechanic so I'm not sure how to interpret this. Thanks guys for your help, Terry

Plugs look ok, plug wires look new, dist. cap looks new. Here's what happens: car idles ok, a little miss. When I drive and accelerate slowly, car misses and sputters, with medium acceleration it's worse, sounds like it might die but doesn't. If I floor it and open up the 4 barrels, car accelerates fine, really takes off....anyone know what might be causing this? Since the carb is brand new, I'm not sure what step to do next.

Thanks everyone,

Terry M.

Sounds like lean mid range to me. You may need to put richer metering rods in the carb. Full throttle sounds like it may be ok, so the jets themselves are ok. Greg

Here's a link to the manual for the Edelbrock Performer carb:

If you are going to tune the carb, you might have to buy a calibration kit to richen the primary circuit. The calibration kit comes with jets, metering rods and metering rod springs of various sizes.

Are you sure you don't have a vacuum leak?

Dave

Hi Terry, Check the near the lower center front area for the carb number. It should be something like 1405, 1406 & etc.

Then go to Edelbrock's web page and download the manual for the performer series carbs. There is extensive tuning info in the manual.

Look up the stock components for rods, springs and jets. Buy a complete set for your carb.

Then remove your carb and install all new stock components.

Cheers, Tim

Tim, good advice I'll do just that. This morning I was considering buying a new Q-jet type carb instead, because I know they are dependable and smooth running, but it seems like a waste of money because this Edel. carb is nearly new.

Thanks again for the help-- Terry M.

-- I just tried this, and yes there is a good gas stream going into the carb from both barrels-- Terry

Dave, I've looked over the vacuum lines, all looks ok. at full throttle the car accelerates real well, but at less than full throttle it still stumbles--Terry

Greg, I think this carb might be running lean just like you said. I took the car in to a speed shop that specializes in Chevys (Corvettes) and that was the first possibility that they mentioned. The car was driven in Nevada so re-jetting the carb might do the trick--- Terry