Quadrajet issue - Page 2

buzzinhalfdozen · 10-04-2013, 10:50 AM

Alan ,carb was off the shelf rebuild to my knowledge. Has stock fuel pump on it though that's no real indicator of correct pressure. After reading the posts I realized I've got a few old tools from back in the carb days that may help on this, thanks for all the input now I have to see when he's gonna bring it over. BTW I tried directing him on checking the PP from the air horn however it's difficult over the phone. Thanks again and I'll update after I've looked at it myself. Man it's been a loooong time since I've seen a carb wish I had a better memory.

Alan Roehrich · 10-04-2013, 05:34 PM

Joe, if it came off a shelf at a parts house, I'd almost bet they've thrown away most or all of the Rochester metering parts, and they've used lead slugs to block the air bleeds in the main metering body.

I used to work for Mayo and Shrum in Nashville, we were the top carburetor shop in this area. It was company policy to refuse to work on remanufactured carburetors unless the work was on a per hour plus parts basis. I don't think I ever fooled with a remanufactured Q-Jet from any remanufacturer that had the original Rochester metering parts, or that did not have the air bleeds plugged. As a result, they all ran at about 8% CO on a 4 gas analyzer, otherwise known as pig rich.

You have to know what metering parts belong in the carburetor to fix it right, but if you have the gaskets, you can at least take it apart and knock the plugs out of the air bleeds in the main metering body, and that should at least make it somewhat useable.

If I can help, or answer any questions, send me an email or a PM, I'll do what I can.

Kevin Panzino · 10-04-2013, 07:20 PM

It's also quite possible it's idling on the secondaries. Improperly adjusted linkage, air valve or sec metering rods set or sticking high will cause it to idle incredibly rich with no fuel at all from the primaries or idle circuit.

buzzinhalfdozen · 10-10-2013, 07:54 PM

OK so I've got the car now, yeah it'll burn your eyes at idle, checked for PP operation piston is pulled down with engine running. So I start looking around and looking down the carb I see liquid fuel dropping on the throttle blades, little on the left, lots on the right, so I'm thinking floats sunk or too high. Pulled carb removed top and level looks normal to me, however I don't have any height chart to work off of. It's been prolly 20 years since I've even seen a Qjet but this looks like it has a cavity for an Mixture control solenoid which has been covered with an alum. plate siliconed in place. carb number is gone (ground off) any general deminsion for the float height? Since it doesn't LOOK high and the throttle blades had minimum opening, any ideas why it's pulling fuel over? Acts just like a holley with a high float level. Thanks Joe

Alan Roehrich · 10-10-2013, 08:36 PM

Set just about any Q-Jet float to 5/16" from the top of the main metering body, without the gasket.

Joe, can you post, email, or PM a picture or two?

MEXJOE · 10-10-2013, 10:29 PM

Heavy float,
Float arms (bent) rubbing on power piston housing,
Needle & seat lift clip is not on correct and binding ( IT DOES NOT! Go through the small holes on the float arm)
??

brent flynn · 10-10-2013, 10:57 PM

I never use the clip...

buzzinhalfdozen · 10-11-2013, 08:26 AM

Alan ,yeah I'll try to get some pics found needle lift clip in well for Mix controll solenoid. I'll measure but float looks pretty close to that measurement.Float not rubbing any where. Looks to me like they took alot of mismatched qjet parts and tried to make a carb out of it. There is some sort of valve in the bottom of the well where I'd say an MC solenoid once sat, seem to recall way back they made a qjet with some sort of secondary enrichment needle or valve in that area. Any way I'll try this weekend to post some pics and hopefully can resolve this. BTW this is a 1971 429 SCJ mustang, I'm lead to believe this is the only year they put a Qjet on this engine.

buzzinhalfdozen · 10-11-2013, 02:44 PM

After speaking with the owner of the car today We've decided to ***** can this carb.Going to try and find a source for a street Qjet for this engine, where's the best place? Needs to have eletric choke and pull offs ect. Thanks Joe

Mark Ugrich · 10-11-2013, 03:26 PM

You could try Sean Murphy. He did the Q jet on my 454 Suburban.It took a couple attempts, but it runs really well.

http://www.smicarburetor.com/

10-04-2013, 10:50 AM	#11
buzzinhalfdozen Senior Member Join Date: Sep 2006 Location: Bellevue Ohio Posts: 984 Likes: 0 Liked 11 Times in 8 Posts	Re: Quadrajet issue Alan ,carb was off the shelf rebuild to my knowledge. Has stock fuel pump on it though that's no real indicator of correct pressure. After reading the posts I realized I've got a few old tools from back in the carb days that may help on this, thanks for all the input now I have to see when he's gonna bring it over. BTW I tried directing him on checking the PP from the air horn however it's difficult over the phone. Thanks again and I'll update after I've looked at it myself. Man it's been a loooong time since I've seen a carb wish I had a better memory. __________________ Joe Buchanan SS/BX 3117

10-04-2013, 05:34 PM	#12
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,105 Likes: 1,561 Liked 1,788 Times in 408 Posts	Re: Quadrajet issue Joe, if it came off a shelf at a parts house, I'd almost bet they've thrown away most or all of the Rochester metering parts, and they've used lead slugs to block the air bleeds in the main metering body. I used to work for Mayo and Shrum in Nashville, we were the top carburetor shop in this area. It was company policy to refuse to work on remanufactured carburetors unless the work was on a per hour plus parts basis. I don't think I ever fooled with a remanufactured Q-Jet from any remanufacturer that had the original Rochester metering parts, or that did not have the air bleeds plugged. As a result, they all ran at about 8% CO on a 4 gas analyzer, otherwise known as pig rich. You have to know what metering parts belong in the carburetor to fix it right, but if you have the gaskets, you can at least take it apart and knock the plugs out of the air bleeds in the main metering body, and that should at least make it somewhat useable. If I can help, or answer any questions, send me an email or a PM, I'll do what I can. __________________ Alan Roehrich 212A G/S

10-04-2013, 07:20 PM	#13
Kevin Panzino Senior Member Join Date: Oct 2002 Location: Pittsburgh Posts: 574 Likes: 298 Liked 747 Times in 136 Posts	Re: Quadrajet issue It's also quite possible it's idling on the secondaries. Improperly adjusted linkage, air valve or sec metering rods set or sticking high will cause it to idle incredibly rich with no fuel at all from the primaries or idle circuit.

10-10-2013, 07:54 PM	#14
buzzinhalfdozen Senior Member Join Date: Sep 2006 Location: Bellevue Ohio Posts: 984 Likes: 0 Liked 11 Times in 8 Posts	Re: Quadrajet issue OK so I've got the car now, yeah it'll burn your eyes at idle, checked for PP operation piston is pulled down with engine running. So I start looking around and looking down the carb I see liquid fuel dropping on the throttle blades, little on the left, lots on the right, so I'm thinking floats sunk or too high. Pulled carb removed top and level looks normal to me, however I don't have any height chart to work off of. It's been prolly 20 years since I've even seen a Qjet but this looks like it has a cavity for an Mixture control solenoid which has been covered with an alum. plate siliconed in place. carb number is gone (ground off) any general deminsion for the float height? Since it doesn't LOOK high and the throttle blades had minimum opening, any ideas why it's pulling fuel over? Acts just like a holley with a high float level. Thanks Joe __________________ Joe Buchanan SS/BX 3117

10-10-2013, 08:36 PM	#15
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,105 Likes: 1,561 Liked 1,788 Times in 408 Posts	Re: Quadrajet issue Set just about any Q-Jet float to 5/16" from the top of the main metering body, without the gasket. Joe, can you post, email, or PM a picture or two? __________________ Alan Roehrich 212A G/S

10-10-2013, 10:29 PM	#16
MEXJOE Senior Member Join Date: Jun 2008 Location: nhranumbers.com Posts: 875 Likes: 137 Liked 165 Times in 51 Posts	Re: Quadrajet issue Heavy float, Float arms (bent) rubbing on power piston housing, Needle & seat lift clip is not on correct and binding ( IT DOES NOT! Go through the small holes on the float arm) ?? __________________ Glen DeMenge 1969 Camaro Stock Eliminator

10-10-2013, 10:57 PM	#17
brent flynn Senior Member Join Date: Apr 2011 Location: Middletown, IN Posts: 593 Likes: 0 Liked 0 Times in 0 Posts	Re: Quadrajet issue I never use the clip... __________________ 1968 Bird/TRW 455/Home ported 13's, '70 Qjet,Holley Street Dominator manifold, Comp Solid FT, 10.817/122.30/1.440 Workin' on E/SA combo 3119 E/SA

10-11-2013, 08:26 AM	#18
buzzinhalfdozen Senior Member Join Date: Sep 2006 Location: Bellevue Ohio Posts: 984 Likes: 0 Liked 11 Times in 8 Posts	Re: Quadrajet issue Alan ,yeah I'll try to get some pics found needle lift clip in well for Mix controll solenoid. I'll measure but float looks pretty close to that measurement.Float not rubbing any where. Looks to me like they took alot of mismatched qjet parts and tried to make a carb out of it. There is some sort of valve in the bottom of the well where I'd say an MC solenoid once sat, seem to recall way back they made a qjet with some sort of secondary enrichment needle or valve in that area. Any way I'll try this weekend to post some pics and hopefully can resolve this. BTW this is a 1971 429 SCJ mustang, I'm lead to believe this is the only year they put a Qjet on this engine. __________________ Joe Buchanan SS/BX 3117

10-11-2013, 02:44 PM	#19
buzzinhalfdozen Senior Member Join Date: Sep 2006 Location: Bellevue Ohio Posts: 984 Likes: 0 Liked 11 Times in 8 Posts	Re: Quadrajet issue After speaking with the owner of the car today We've decided to ***** can this carb.Going to try and find a source for a street Qjet for this engine, where's the best place? Needs to have eletric choke and pull offs ect. Thanks Joe __________________ Joe Buchanan SS/BX 3117

10-11-2013, 03:26 PM	#20
Mark Ugrich Member Join Date: May 2011 Location: Auburndale,Florida Posts: 220 Likes: 29 Liked 71 Times in 38 Posts	Re: Quadrajet issue You could try Sean Murphy. He did the Q jet on my 454 Suburban.It took a couple attempts, but it runs really well. http://www.smicarburetor.com/