Question for Lars
Thread Starter
Instructor
Joined: Aug 2000
Posts: 118
Likes: 0
From: Union Ky
Question for Lars
Got the Q/Jet tore down for a rebuild and found that someone has taken a hacksaw to the center two brass tubes on the carb top (see picture). Any idea on what in the heck they were trying to do by making these tubes shorter and is it worth trying to rebuild this carb for street use on my '74?
Thanks...Jack
Thanks...Jack
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
The center ones that look like the ones that are cut off (can't tell about the outside tubes) are the Secondary Main Well Air Bleed Tubes. I thnk they allow air to bleed back into the secondary well to allow fuel to flow in the Secondary Fuel Feed Tubes. Someone aparently thought cutting them would allow more air, therfore more fuel to flow.
Don't know how it worked out, or if it matters.
Are the Fuel Feed Tubes cut too?
Don't know how it worked out, or if it matters.
Are the Fuel Feed Tubes cut too?
Drifting
Joined: Sep 2004
Posts: 1,959
Likes: 1
From: North Bend Ohio
These tubes had crimped ends and calibrated air bleed holes originally. With that removed I would think the secondary metering would be leaner than is desirable. I have replaced the larger secondary fuel tip in pickup tubes but never the smaller air bleeds. You may need a new carburetor top.
BigBlockk
Later.....
BigBlockk
Later.....
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,391
From: At my Bar drinking and wrenching in Lafayette Colorado
Those are fuel emulsion tubes, and you need them. Get a junk Q-Jet and yank the tubes out of the airhorn and install them into your carb.
Lars
Lars
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
Originally Posted by lars
Those are fuel emulsion tubes, and you need them. Get a junk Q-Jet and yank the tubes out of the airhorn and install them into your carb.
Lars
Lars
Is that the same as air bleed? or was I looking at the wrong pic in the book? And what is the function of the tubes?
Dan
Drifting
Joined: Sep 2004
Posts: 1,959
Likes: 1
From: North Bend Ohio
Originally Posted by SIXFOOTER
Hey Lars;
Is that the same as air bleed? or was I looking at the wrong pic in the book? And what is the function of the tubes?
Dan
Is that the same as air bleed? or was I looking at the wrong pic in the book? And what is the function of the tubes?
Dan
BigBlockk
Later.....
Last edited by BigBlockk; May 2, 2006 at 03:25 PM.
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Melting Slicks
Joined: Mar 2006
Posts: 2,465
Likes: 0
From: Orange Park Fl
The ideal standing height for these tubes is exactly one inch. Often they are not imbedded deeply enough into the air horn and stick too far into the emulsion wells, impeding secondary fuel flow. That is very common and is usually not any real problem except for serious performance use. The previous owner probably heard that and decided cutting them off was the right solution (a little knowledge is a dangerous thing!). Actually, to get the ideal standing height, you need to fabricate a special tool by drilling and counter sinking a peice of aluminum rod. Otherwise, just tap them in carefully so as not to damage the ends, and live with them a little too far out. You'll probably never know the difference. God bless, Sensei