Scottd

Gents, I installed my Q-jet tonight. The choke is the Edelbrock big block model (ONLY difference between BB and SB kits is length of rod). The way it is currently installed, it sits at an awkward angle and just doesnt look right. Do I have it installed correctly? Is an electric choke any easier to install?

Lastly, how do I adjust this thing? (yeah, I know I have to bend the rod...but based on what? Full closed when cold, full open at???)



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AQUILA163

Yes. Can not tell from pic if it iis adjusted correctly though.

Scottd

That was also what I was wondering. The instructions say 'bend rod'...not real enlightening. This is my first thermostatic choke so any adjustment tips would be appreciated.

hugie82

On a cool morning in upstate ny you want the spring adjusted just enough to close the choke flaps all the way. If you put too much tension on closing the flaps, it will take forever for the choke to kick off.

After that you can set your fast idle.

AQUILA163

Adjusting these are more art than science.
Bend the coil rod when completely cold just enough that the choke door has a little tension closed. You need a vacuum pump to hold the choke brake open and bend the rod so it opens the choke door about 3/16 inch. Then with the choke brake still under vacuum bend the rod to the secondaries so light pressure is needed to open the secondary flap. Be prepared to make adjustments to any of these rods if,,, the choke. Opens to soon or too late,,, the car starts and stalls cold (choke door opens too much or not enough after start up) or if you get a bog when the secondaries open. More art ten science. Good luck. If you have any questions I'll check back.

Scottd

SERIOUSLY? Can someone explain WHY they make this so difficult? I was very hesitant to switch to a Q-jet but Ive got a spread bore manifold (didnt match my edelbrock) and Ive heard so much (good) about Q-jets and their off idle acceleration.

Aquila, you seem pretty well versed in this. Mind if I PM you with my tuning issues on this one? (I dont know shi+ about Q-jets, Brocks and Holley's Ive got a decent understanding of, but these things are all levers and doors and shi+.....)

Shark Racer

Get a quadrajet with an integral choke (preferably electric), much easier. Just twist the cap like pretty much any other electric choke.

AQUILA163

Yea you can pm me. Qjets I think are better for all around up to about 275 duration camshafts. Its worth the effort and not that hard,just difficult to describe. Shark is right about electric choke being easier but thats a whole change over from where you are now so we can get this right. To bend the rods just use 2 needle nose pliers and patience. If you dont hane a vacuum pump, a vacuum gauge with a hand pump is cheap and a handy tool to have.

Scottd

Im not going to lie.....this setup has me completely perplexed. Lars did the rebuild so Id like to assume all the rods (choke pull off) have been set correctly. Im assuming all I have to do is adjust the length of the choke rod.
Is there a decent tutorial out there n setting this choke? Ive searched youtube but all I can come up with is an q-jet with electric choke.
I feel silly that this little adjustment has me so stumped.

Shark Racer

Lars' Q-Jet Tuning Paper (email him for latest, although you can find historical versions with a search) will have details on setting up the divorced choke.

I've never worked with one, myself.

AQUILA163

Not sure how you've made out, but if no one bent the rods up they are probably pretty close. You won't hurt anything by putting the carb on and starting it as is. Put it on and let us know how it runs.

Scottd

I got it hooked up, went to start it and fuel immediately started pouring out of every orifice. The carb was wet tested before it was shipped back to me and sat in my garage for almost a year until I got back home and could install it. Its all gummed up in the inside. Its going back to Lars for a rebuild rebuild. 8*(

MakoJoe

How did it run when cold is the way to tell. RPMs should be about 1200 when cold than with a quick pound of the throttle once the intake is warm should kick down to 750 RPMs. In gear should idle at 500 rpms on an automatic tranny the manual tranny will maintain the 750 RPMs. When you reach these settings you know it is setup right.

calwldlife

uh what?
fresh build on shelf and then that?

wow, just don't make sense.

jnealg

Sounds like the needles are not seating.? Gummed up from time on the shelf.

Just my highly uneducated guess.

AQUILA163

I opened a carb that was sitting on the shelf and found an insect nest in it. That'll stick a float open.

Shark Racer

A year is plenty of time for a carb to varnish up.

And varnish is nasty stuff.

calwldlife

I was under the impression it was rebuilt then put up.
not used and then put up wet.

Shark Racer

It only takes a little bit of varnish to make a needle fail to seal. "Gummed up inside" sounds like it was put away wet...

7T1vette

If it was not 'dry' and sealed-up when it was stored, you have no idea what it looks like internally.

The only way to properly set up that carb and choke is to find a Chevrolet Chassis Service Manual (assuming that it's a Chevy carb) for the year that carb was produced and follow the instructions on choke and carb adjustments in the "Fuel System" section of that manual. Short of that, you need an expert who knows how to 'wing it' and get the setup right.