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Topic: q-jet float level adjustment

in Forum: C3 Fuel, Emission Control, and Exhaust Systems

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q-jet float level adjustment (6/16)
1/26/08 9:53pm

dcherr
Former Member
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Elkhart, IN - USA

Vette(s):
1975 Red T-Top 1972 Red Convertible

Joined: 10/7/2007
Posts: 209

I just took my Q-jet off to rebuild. Wits%20End

Got a book ( How to rebuild and modify Rochester Quadrajet Carburetors by Clif Ruggles ) It goes into great detail on how to disassemble inspect and reassemble.

Let you know how it runs when I get it done. Thumbs%20Up

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q-jet float level adjustment (7/16)
1/27/08 12:36am

Adams' Apple

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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 20129

I have Lars Grimsrud's article on "How to Tune a Q-jet" as a MS Word doc, if anyone wants it...I'm not sure if it is e-mail friendly, but I'll sure give it a try.
It is VERY detailed, spec-wise, with no pics, but a lot of tuning tips.

btw, the best "quick test" for water in the fuel is to drain some out in a clear container, and let it sit. The water will separate, and settle to the bottom. It will be quite noticeable. Also, you can get a really bright flashlight, and look down into the fuel tank from the filler. If there is a lot of water in the tank, it will be visible at the bottom. (This is much easier to do on the pre-75 cars than the post-75 cars...)

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Joel Adams
C3VR Lifetime Member #56
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

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q-jet float level adjustment (8/16)
1/28/08 1:58am

daveo76
Former Member
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Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

Joined: 8/25/2005
Posts: 857

Thanks for the scan of the chart, Tom43xy. Do you mean both should be 13/32"? (9/32" looks like the measurement for the accelerator pump). The 13/32" is 3/32" different from what I set mine at -- interesting how the two carb kits gave such different numbers. I'll try yours, though, since it actually references the carb number. Guess I'll have to pull the top off the carb again. I also have the Cliff Rugles book - very good book, but it's weak on the issue of the float settings.

Thanks, Joel for the tips. If you get a chance you could try to email me the Q-jet tuning article. daveo76NOSPAM@comcast.net. Thanks - I'm always willing to read more about them. I want to stick with the Q-jet if I can! And I looked in my gas tank but couldn't really see much. I'll drain some fuel soon to see if that tells me anything.

There were some other posts in the last few days with similar problems (rough running, missing, backfiring) and one of the possible causes given was a sticking exhaust valve. I'm wondering if this could be me since my problems definitely seem to be more prevalent on the right cylinder bank. I've got good compression, but if it sticks intermittently.....???

(email addy modified for your protection)Adams' Apple2008-01-28 06:29:13

______________

1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

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q-jet float level adjustment (9/16)
1/28/08 9:29am

Adams' Apple

On it's way, Dave...

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q-jet float level adjustment (10/16)
1/28/08 11:35pm

tom43xy
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Littleton, CO - USA

Vette(s):
76 corvette, L-48, Flame Red

Joined: 2/5/2006
Posts: 50

Daveo76:
You are correct. I did misread the chart and the correct setting is 13/32". I confirmed this is the same setting on the instructions from both carb kits I have used. Sorry that I misquoted it. Now I'm second guessing what setting I used on mine (I think I used the right measurement, but will probably pull off the top to double check).

As someone else noted, you can't really tell about water in the tanks with bladders. The bladder is black in color (at least mine was), so you would need a lot of light and a bigger hole than you have through the fuel filler.

I also have the Lars Grimsrud article electronically and can e-mail it to you if you have any trouble getting it.

Thanks

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q-jet float level adjustment (11/16)
5/16/08 10:40pm

mmrdl1971

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Wichita, KS - USA

Vette(s):
1971 Bridgehampton Blue Coupe

Joined: 7/5/2005
Posts: 31

Can I get one of you to send me the Lars Article on Tuning. I had my carburator overhauled but the idle needs tweeking and the idle mixture is off. I would have used him but he was down for a while so I had it done locally.

Thanks

______________

Mike & Marcia

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