I am rebuilding my first carburetor (after taking a similar 1920 apart and putting it back together for my own practice), and I have a question. After taking the metering body off, there was a small silver plug that fell out from on top of the block. Flipping it over, a little valve of sorts that probably feeds fuel to the main jet fell out too, as well as a sliver of metal from somewhere. I noticed as well after I took the jet out is that there is a worn, carboned looking place where the needle part of the valve may have bottomed out or done some damage. There was carbon buildup in the valve thing that I have since sprayed out clean. All check balls move freely and other brass plugs are in place, no damage. My couple of questions: should I gently tap that plug back into the hole, or try to locate a new one? Also, is that worn spot behind the jet normal? I have a 1970 Holley 1920, using Mike's Carburetor Rebuild kit.

This is the silver plug and the sliver of metal:
[img][img]http://i1065.photobucket.com/albums/u383/Katie_Pype/Facebook/FABO%20Photos/10353042_1296983500364086_4187386645135315380_n_zpsjzhx1fuc.jpg[/img][/img]

Top of the metering body, where the silver plug fell off of one of the holes, I am guessing the one on the top?
[img][img]http://i1065.photobucket.com/albums/u383/Katie_Pype/Facebook/FABO%20Photos/11048767_1296983467030756_5978343894982956339_n_zpsnp61qhin.jpg[/img][/img]

The valve and the main jet, a size 56. I have since cleaned the gunk and carbon in both of them:

[img][img]http://i1065.photobucket.com/albums/u383/Katie_Pype/Facebook/FABO%20Photos/11427703_1296983400364096_2612780077275492712_n_zpsurplkshg.jpg[/img][/img]

And it is hard to see, but that is the tip of the valve behind the jet, and underneath there is a indent with carbon buildup:

[img][img]http://i1065.photobucket.com/albums/u383/Katie_Pype/Facebook/FABO%20Photos/11402932_1296983440364092_8381928945677014909_n_zpsqf20qyko.jpg[/img][/img]

Thanks so much for the help![/img]

That tube is idle fuel. The small part behind main jet at bottom of tube is idle fuel feed restrication. Quite small .028 to .030 around there,even a little crud there will lean out ideal. At the top of that tube there is hole in metering block,this hole is from idle air bleed. That Aluminum expansion plug 5/16 Walker part no 85-53,covers this area up.Creates chamber were air and fuel are mixed together for the idle circuit. If that plug leaks air ideal mixture will be lean. If leaks too much idle circuit may not work at all.

Worn spot behind main jet is a screw driver mark. Used as a pry bar to lift idle tube while taping metering block against work bench. To reinstall use a small bolt to tape down till seated. Light tapes Idle tube in freezer helps. The silver plug Walker part no 85-53 should be squared up in metering block and pressed in. Small vice or good pliers, must stay square in hole. If mikes carb can not get this,I have extra send pm. If you need to get this runing but in there the best you can and put epoxy on top of plug to seal out air and hold it in place

That idle tube is already out.I would find a place that has small numbered drill bits and let them clean that tube and check size for future reference. Later on maybe try tube with bigger hole. The carb was not set up for todays fuel. For example pull out tube measures .028 . Use replacement tube measures .029 just a little richer.

Hmm, that makes a bit of sense. The reason I pulled the carb in the first place is because my engine was only able to idle in the 1500+ RPMs, and anything below 900 and it would choke up and die. It would also die when in park and idle when warmed up. Acted like it wasn't getting enough fuel either.

I tried looking in Mike's Carb but did not find the right size of plug, so I will PM you. But with the circumstances (my car is currently in my high school's shop and I need to get it home) I need just enough to get it home, so I will try the epoxy idea and would just pull the block out when I would get a new plug. Do they sell those in auto part stores like NAPA? Is there any specific for fuel? EDIT: I did find the plug underneath the parts number, whoops. And since the shipping location of his place is within the state it will be here by Tuesday for sure. Thank you anyways.

The hole really cleared up when I pressed the straw of the cleaner to it and really blew the cleaner through it until it sprayed across the garage! One of my classes has a few tiny drill bits for jewelry drilling so I could see what size it is.

Thanks so much for the info, I really hope that me cleaning it out will help my problems!

http://www.slantsix.org/forum/viewtopic ... c&start=90 Thats a good thread on 1920 idle air bleeds, Some of these carbs had an adjustment screw in that area. It came in from side of carb. Made the flow of air threw idle air bleed adjustable. Less air richer idle circuit, more air leaner.