68 AVS - remove lead plugs?

I'm rebuilding my '68 AVS with the single air bleed adjuster and the two lead-plugged mixture screws. Should I remove the lead plugs or not? Engine is stock, but I live in California, so the gas is crummy. Thoughts?

Am I mistaken in thinking the ones with the two leaded plugs covering the lower idle mixture screws used the one bigger screw in the middle for the same purpose? Might post up a picture, but that is coming to mind. Also Scott Smith at Harms restoration would be a good person to talk with.
Matt

these are the two types of adjusting screws I was referring too. Found these quickly on ebay so not a correct to part number of your carb, but hopefully it helps explain my reply.

Mine is like the one in the top photo. I know Scott. I was considering having him do the carb for me, but I didn't want a complete restoration on it, so I decided to do it myself.

If its like the top picture, I do believe the one center screw adjusts the idle mixture, unless you think you need to pull the lead plugs, install the two other style mixture screws, and plug the existing center hole. Not sure if that would give you any more adjustability over the one single style screw, or not.
Matt.

removing the lead plugs at the bottom of the carb will expose the mixture screws. these are for gas mixture. the top left hand thread screw is for air only. it's kinda like an adjustable air bleed. the bottom mixture screws can noticeably improve idle quality. removing the top of the carb and taking out the two clusters will expose the emulsion tubes and idle jet (the small brass tube). enlarging the idle jet orifice, especially on automatic trans cars, along with working mixture screws can make a big improvement in idle and low speed engine operation.

When you get to the idle mixture screws, if they are frozen be patient. You may have to use heat with a penetrating oil on and off for a couple days. Because the alternative is drilling them out and can be tedious, especially the first couple times. The above post is correct in that the screw in the middle only trims air, and is good for maybe a full point AFR.

I've found that without increasing the size of the idle jet there may not be enough adjustment in the mixture screws to satisfy the fuel needs at idle and low speed. this is especially true with automatic carbs. manual carbs have a larger idle jet but it's about borderline with todays fuels.

The answer is yes. You should remove them to fully clean the carb. Plus ensure they are set right for todays gas and your car as mentioned above.

This is timely and helpful for me too, as I've been unhappy with idle performance on one of mine. When you talk about the idle jet, you mean just drilling out the end of the small tube? Recommendation on how much enlargement is needed? Thanks in advance!

Done meant to hijack this thread i have a 68 avs where the single screw that does absolutely nothing when trying to make adjustments. Thoughts?
Thanks

yep. drilling the small tube. generally automatic trans carbs have a .031" idle jet and manuals .035". I run .039" with a 4618avs. mine won't idle worth a crap at .031". you can start at .035" and go from there. I leave the idle air bleeds, bypass, and economizer alone. I also use the edelbrock mixture screws. they have a different tip that doesn't require backing out as far as the factory mixture screws. there are some carter afb/avs tuning tips from carter out there on the web.

Just what I needed. I'm dangerous now! Thanks much!

I would say be careful. One man's engine is different than another's. Once you open it up, you can't go back to smaller. So I would make sure everything else normally check for proper idle and cruise is checked first.

Having a heck of a time getting the last bit of one of the plugs out. The first one came right out with the second left-hand drill bit. It unscrewed the plug perfectly. I was able to easily remove that screw. The other one is being more difficult. The drill got a tiny bit off center and now I am slowly trying to get the last of the lead out. I can move the screw a little bit, but the threads still have remnants of lead in them.

Any ideas?

you can go back. done it several times testing.

A sharp angled pick will help you get the lead out o the threads.

HF has a set of cheapies that have different angles that will likely work for you

A bottom tap may help clean much of it out.

That's what I ended up using. Had to order it from Amazon.

This pic may be of help to you. Ron

Just closing the loop on this thread. Last weekend I put the carb back on and got it running. Runs pretty good. I need to fine tune it a bit more, but haven't had time. Seems to idle better than before.