Rochester Quadrajet Idle Tube Removal

Rochester Quadrajet Idle tube removal
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[@george1la]

Great video to show just how to get out the tubes. I did not use enough heat and did not cut off the tip of the screw so I did not get them out the first time. Now I know what to do. Thanks.

[@shadvan9494]

Harold, great video. I just want to add 1 thing. the Idle down tubes are actually made out of 2 pieces. there is the collar and a tube its self. you can use a .090 punch to drive the tube down enough to disengage it from the collar. then use the screw method to pull the collar out. that way you are not shortening the tubes. the length of the tube and collar is important to the getting the right air to fuel emulsion at the needles. By drilling it and shortening the collar by filing, it raises the tip of the downtube in the fuel level that is in the downtube well. which in turn leans out the mixture at the idle needles. this causes the needles to need to be turned out more than necessary for a decent idle. It will also cause off-idle lean condition when the carb it transitioning from idle to cruise. this due to a lean mixture at transition slots in the base, as they pull air/fuel mixture from this same circuit. this happens just before there is enough air flowing threw the primaries to pull fuel from the main circuit. if you have a chance check out cliff ruggles book on the Q-Jet. it has some good info on the idle tubes and their length is important to a proper idle mixture.

[@backnine]

Hi Shad These are pickup tubes. They are always submerged in fuel. The emulsion takes place as the fuel crosses over to the down circuit and also as it enters the base plate circuit. The reason I say drill it down a little is that if you try to punch it down 8 out of 10 the collar goes with it. If you punch it down too much it will bottom out and bend the tube. I have never seen any difference in the Idle or transition circuit after doing this. You can also buy replacement tubes and collars. When I did the video I was going to show how to punch the tube through the collar enough to engage the screw and the collar started going down with the tube. Like I said this happens 80% of the time. So I decided to show it this way. Watch my rebuild video and I show how to clean them in place. Thanks for the input. Harold

[@KevinRHill1]

I NEVER drill them. Use a punch as Shad mentions.

[@thisisyourcaptainspeaking2259]

I've seen aftermarket rebuilds where the replacement tube is a single piece, these were installed by the carb rebuilder. So if driving the inner tube down isn't working, it's probably been rebuilt and the original tubes have been replaced with the one-piece type. I don't know how many there are out there, I've run into this only a couple times. Drilling the top as shown does work fine and doesn't hurt anything if you feel the need to remove them.

[@brianb5779]

Nice to see good videos on these procedures so thanks man.

[@thisisyourcaptainspeaking2259]

Don't file the idle fuel metering tube if you remove it this way (see Cliff Ruggles' book), just press it back in flush to keep the original depth. I find a smallest size paperclip is about .0315" and will fit through the precision calibrated small end at the bottom of the tube thus no need (usually) to remove this tube for cleaning below. ie: If the 0.032" calibrated hole at the bottom of the idle feed tube is restricted with dirt/corrosion debris, you will have difficulty adjusting idle mixture fuel (lack of idle fuel). IMO, typically it's unnecessary to remove this tube unless maybe the bowl is badly corroded so I just carefully push a smallest size paperclip wire that's 0.031" diameter down through the tube to a depth of 1.5" to clear the calibrated orifice at the bottom then blow out any remaining dust, etc. using carb cleaner solvent and ~80psi air. Removing the screwed-in primary jets helps to view this lower bowl area for corrosion and make it easier to blow out any loosened debris.

[@petratical]

"This is Your Captain Speaking" Dang, wish I had thought of that one, very cool! Buying my rebuild kit by Elkin tomorrow at NAPA. Thanks Captain

[@khalillayton110]

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[@khalidtrevor9449]

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[@khalillayton110]

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[@billygoat1708]

Wrong. You don't drill the idle tube. You just use a punch to tap the idle tube slightly for clearance for the drywall screw. Then make it flush before re-installing. Also, I have never had to heat the casting. Get a set of pin drills and open the bottom of the idle tube 10% to richen the idle. They are around .032" diameter (varies slightly) so you would use a .035" drill. Many of these were "smog" carbs for emissions.

[@franciscotrujillo4961]

If the air-fuel mixture comes out rich in fuel, you may need a smaller tube, all taking into account that the jets, primary needles, buoy, needle, needle seat, are new and with their corresponding gauges? Greetings and thank you

[@tunnelportterror]

All you need is a long drill bit, drill the idle tube out from the top to clean it, let it in place. Nothing is gained removing it. Long .035" to .043" drill bit. Hand pin drill vise.

[@NilsJakobson]

If you drill the tube and file the collar flush then youre changing the depth of that idle tube as a result. I would say dont file the collar flush and actually dont even pull the tube from the collar, just install it back the way it was, no need the tube to be flush with collar. But better is not to drill at all, try Ruggles method before considering drilling anything..

[@thisisyourcaptainspeaking2259]

True.

[@byronp1082]

So after just doing this a few hours ago, I started out with the punch method (Bought Cliff Ruggles book a couple months back ) and turned out to be a frustrating fruitless experience, screw wouldn't bite, tried your method Harold demes and it was a piece of cake..... I think it's sized better for the screw this way. No disrespect to Cliff Ruggles his book is awesome, but just my experience with this for the first time to make performance mods. Awesome videos Harold Thanks!

[@thisisyourcaptainspeaking2259]

Could be your carb was remanufactured. Sometimes they replace the factory tube with a 1-piece tube and Cliff's method using a punch won't work in that case you have to drill but still IMO in most cases removing the tubes is unnecessary.

[@stevepacker2327]

@@thisisyourcaptainspeaking2259 Would you happen to know whether or not a factory replacement carburetor would have a one piece or 2 piece idle tube?

[@thisisyourcaptainspeaking2259]

@@stevepacker2327 Concerning the quadrajet, many if not most of the jobber reman carburetors I've come across have single piece idle tubes. The idle tubes available in the aftermarket may or may not be two piece but last I noticed were two piece. The actual orifice is located at the very bottom of the tube, so unless you need concourse restoration or are just interested in getting it whistle clean, you can make the hole in the top larger (ie: by inserting a drywall screw and cranking it in) without creating an issue. You might find some heat from a butane or propane torch helps loosen it up but they'll come out with a good bite and some tugging. The idle tube needs to be the correct depth and the orifice needs to be the correct size, I wouldn't try drilling it larger. The idle circuit is working correctly if you can control idle mixture using the two idle mixture screws. The orifice at the bottom of the idle tubes tends to get restricted with debris.

[@thisisyourcaptainspeaking2259]

@@stevepacker2327 Hopefully I answered your question, to me "factory replacement carburetor" could mean several things. You can order replacement tubes in case they get destroyed, I doubt you'll need to though.

[@stevepacker2327]

@@thisisyourcaptainspeaking2259 There is always a chance I might mess up when I try to remove the idle tubes. I should have mentioned that my carb was technically called a service replacement carb 17054905. Since there were problems with many of the original q-jets many were replaced under warranty. Good to know that I can get a replacement idle tube. My car is a baseline 73 455 with 400 4x heads. I do plan on increasing the idle tube orifice at the bottom a little. I will be installing a ram air IV cam. You are very quick and helpful. Thank you Cap.

[@TheHomy70]

when a Rochester carb is sent out to a rebuild place, why is it never mentioned as to cleaning these tubes or do they just run a fine drill down to clean them and call it a day.

[@thisisyourcaptainspeaking2259]

The rebuilds I've seen look like replacement idle fuel well tubes, slightly different from the originals and some are one piece type.

[@tunnelportterror]

It doesn't have to be original depth

[@user-nx2xi3hx2k]

الرجاء ترجمه الى العربيه

[@scotts439]

Harold, could you send me contact info for the plating? Are you taking just plating work? thanks, -scott

[@backnine]

Hi Scott I do carburetor restoration work also. Here is my email. [e-mail] Thanks Harold