[Heavy6clyCHEVY]

I got rid of my 250 straight 6 for a 307 marine V8 =)
i got a Quadrajet b barrel carb. off a 1967 327

my problem is this, A) the choke sticks open, requiring me to close it manual when the car is cold to aid in starting. and B) when i go wide open throttle, acceleration basically stops. the engine bogs and it sounds like it its being coked out (too much air or fuel, or the secondaries arnt opening )

I have the shop manual and a Chilton book but they have been no help. it runs great in the driveway, and after its warm, and the plugs are a perfect tan color. the carb is totally rebuilt and should be perfect for this motor, but im lost. this is my first Q-jet

so i need help figuring out this choke, for starting; and bogging for when i get on it.
thanks for any help!
:beers:

 

[slingslingbinks]

Hey Erick. I'v ran a q-jet for 10+ year's with out a choke, I wired it open and just pump the dicken's out of it and get it started. got tired of trying to get the auto. choke right and gave up. On the bogging, make sure your secondary rod's are still connected to the hanger. Some times they come off when putting the hanger on and dropping them in place. Also there is a lever that swing's out of the way when the choke is all the way off to let the secondary's open. i alway's leave that lever out so the secondary's will alway's work. Pls check the rod's and report back. C-ya Scott

 

[Schurkey]

my problem is this, A) the choke sticks open, requiring me to close it manual when the car is cold to aid in starting.

http://www.chevelles.com/techref/Adjusting_Automatic_Chokes.htm

and B) when i go wide open throttle, acceleration basically stops. the engine bogs and it sounds like it its being coked out (too much air or fuel, or the secondaries arnt opening )

Fix the first problem, (the choke) MAYBE the second one goes away. Many Q-jets have a latch that prevents the secondaries from working until the choke is fully open. It may be mis-adjusted. There are a dozen other possibilities.

I have the shop manual and a Chilton book but they have been no help.

You need THIS book.

Amazon.com: How to Rebuild and Modify Rochester Quadrajet Carburetors (S-a Design) (9781932494181): Cliff Ruggles: Books

it runs great in the driveway, and after its warm, and the plugs are a perfect tan color.

Today's gasoline doesn't leave a perfect tan color.

the carb is totally rebuilt and should be perfect for this motor, but im lost. this is my first Q-jet

The fact that your choke won't work properly is an indication that the carb was not rebuilt properly.

 

[Heavy6clyCHEVY]

Well when i rev it in the drive i see the secondaries open ok. so im sure theyre opening when i drive..... pretty sure...
but the choke has to do with that plastic cam thingy... on the passenger side. when i open the throttle, something moves out of the way on the same side, and the thermostat spring is free to close the choke all the way, making starting (usually) easy.
ill post a photo later.

im more concerned with the "powerband"? i can slowly accelerate steadily giving it more & more throttle to a point, then you feel the momentum arrest and hear the pitch of the exhaust change, bog, and i need to back off the throttle to a more moderate acceleration rate. it should go balls out fast! X(
what doses this sound like? a float maybe?

 

[slingslingbinks]

Check those secondary rod's to see if there still hooked to the hanger.

 

[slingslingbinks]

http://www.vetteprojects.com/kstyer/quadrajet.htm

 

[slingslingbinks]

 

[Verle]

Another possibility on the bog when you try to accelerate.
Above the back butterflys is a large air valve that is opened by engine vacuum. It is held closed by a small spring that is enclosed by part of the carburetor top. If you turn the carburetor up-side-down you can see the spring on one end of the air valve shaft. Also on the under side is an adjustment screw to set tension on the spring. If the spring is too loose, the valve will open too soon and the engine will bog.

A carburetor set up for a 454 may allow the air valve to open too soon for a 307.

 

[Heavy6clyCHEVY]

well i finally got it as good as its gonna get
i think that this carb is just too damn big for a 307
cause now, it bogs, but its not a struggling bog like before. its clearly a "wholey crap this is a lot of gas!" type bog..... if that makes scene

it was a combination of a cracked vacuum canister, and a maladjusted rear butterfly tension spring. and i had a pinhole leak in my aluminum fuel line i installed last year... idiot X(
it has GREAT even power now, so long as i dont puch it at too low of an RPM

so yeah, thanks a lot everyone! ill keep this carb for the 396 big block! but for now, this 307 is gonna get a 2 barrel set up for optimal driveability
THANKS!! =) :beers:

 

[Buzzbomb]

Instead of going through all the trouble with adapters and intakes, why not just fix the Qjet right? A Qjet is a carb that gives only what you ask- when set up right. The '67? Pontiac Lemans 6 banger came with a Qjet are ran just fine. Take a step back, do some research, and approach it again. It WILL run fine on your engine. You need to do like Verle said and tighten up the secondary air door spring tension screw for YOUR engine. Not hard at all..If you want, tighten it up tight, and then loosen it a little bit at a time. I'll bet you see a difference from that.

As for the choke, my Qjet will not start my car with no choke. I can pump until the cows come home, but if that choke is not fully closed, no dice. I set it manually to fully close when over 70 degrees, but any other time it's fine. Just too lazy to set it during winter and summer, I guess .. NO big deal, it's the best carb ever, IMHO. Took a lot of convincing for me to believe that, but I believe it now.

Like I said, no reason that Qjet can't run right on your engine.

 

[JWagner]

"but for now, this 307 is gonna get a 2 barrel set up for optimal driveability "

No, don't do this. I have Chevelles with both the 2 barrel and the Qjet. The Qjet has better overall driveability. You need to work on the Qjet you have to get it running well. Do some reading and learn about setting the secondaries properly. You will be rewarded with better performance.

 

[Schurkey]

I ran a Q-Jet on a 283.

It'll work just fine...if you tune it properly.

 

[johnretired]

I got rid of my 250 straight 6 for a 307 marine V8 =)
i got a Quadrajet b barrel carb. off a 1967 327

my problem is this, A) the choke sticks open, requiring me to close it manual when the car is cold to aid in starting. and B) when i go wide open throttle, acceleration basically stops. the engine bogs and it sounds like it its being coked out (too much air or fuel, or the secondaries arnt opening )

I have the shop manual and a Chilton book but they have been no help. it runs great in the driveway, and after its warm, and the plugs are a perfect tan color. the carb is totally rebuilt and should be perfect for this motor, but im lost. this is my first Q-jet

so i need help figuring out this choke, for starting; and bogging for when i get on it.
thanks for any help!
:beers:

You are aware that with carbs you MUST push the throttle to set a choke, right?
I agree get this Q-jet tuned right and be happy with it.

 

[slingslingbinks]

I'v thrown many holley's in the trash can and used a q-jet instead. Mabey it was a fact that the holley's were the spread bore version that i had and tossed. The book that Doug Roe wrote was my bible on q-jet's and wore the book out and had to get another one.

 

[Greg Gessler]

I hope you stuck with the Q-Jet and sorted it out properly. It is a superior carb.

 

[slingslingbinks]

Hey Greg, Nice website, I'll remember it and i see it has the q-jet book from Doug Roe. C-ya Scott

 

[1224]

I ran a Qjet on my 307 with absolutely NO problems right out of the box. I suspect that the main jets have been changed from stock. I would find the specs for this carb and go thru the whole carb checking to see if the jetting and adjustments are different from stock.