Author Topic: Quadrajet problems  (Read 5428 times)

Offline mountaindrew

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Quadrajet problems
« on: May 01, 2010, 08:51:55 am »
I adjusted my idle yesterday with a vacuum gauge and got a good idle and highest vacuum when the idle screws were fully seated.  I was getting about 18.5" on my vacuum gauge and was holding steady.  I sprayed some carb cleaner around the base of the carb and vacuum hoses to try to find a leak.  The only place I found of was when I sprayed some around what looks like the throttle linkage bearing place on the driver side of the carb.  But the engine choked out when I sprayed cleaner there, instead of picking up speed like I thought it would.  I think something's not quite right.  Guidance please?
1986 Chevrolet C20 Silverado, C6P, 454, TH400, 3.73, FF
oil and trans cooler, 6 qt oil pan, p/w, p/l, air, cruise
17" Dodge wheels & E rated Michelins, Curtis hitch, Prodigy, Equal-i-zer

Offline Captkaos

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Re: Quadrajet problems
« Reply #1 on: May 01, 2010, 11:15:34 pm »
It the throttle shaft loose?
you probably need to bushing the shaft.  I would imagine it would be a bad leak if the needles are seated.

Offline mountaindrew

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Re: Quadrajet problems
« Reply #2 on: May 02, 2010, 09:07:47 am »
It has some noticeable play in the shaft area.  Do you know if the bushing come in the standard local part store rebuild kit? Also I tried to adjust the idle down from 1000 to around 800.  The screw was backing out but the idle throttle plate wouldn't come back any more.  There was a gap between the  screw and bump stop. Any adjustment for that?
1986 Chevrolet C20 Silverado, C6P, 454, TH400, 3.73, FF
oil and trans cooler, 6 qt oil pan, p/w, p/l, air, cruise
17" Dodge wheels & E rated Michelins, Curtis hitch, Prodigy, Equal-i-zer

Offline jaredts

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Re: Quadrajet problems
« Reply #3 on: May 02, 2010, 11:21:00 am »
Bushing kits can be found online.  I don't think you can get one at a parts store.  You're probably just as well to use it as a core for one that has been rebuilt.  They usually have been bushed and are better than new.  You can do it yourself with a drill press and the kit if you choose.

Offline mountaindrew

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Re: Quadrajet problems
« Reply #4 on: May 02, 2010, 02:21:13 pm »
Thanks for the help.  Where do y'all like to get your reman, ready to drive Quadrajets from?  Is there a preferred or recommended vendor?  I am eyeballing this site http://www.guaranteedcarbs.com/?gclid=CMDR_YKbtKECFRRM5Qod0QigAw because of the price and the monkey  ;)
« Last Edit: May 02, 2010, 02:45:04 pm by mountaindrew »
1986 Chevrolet C20 Silverado, C6P, 454, TH400, 3.73, FF
oil and trans cooler, 6 qt oil pan, p/w, p/l, air, cruise
17" Dodge wheels & E rated Michelins, Curtis hitch, Prodigy, Equal-i-zer

Offline VileZambonie

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Re: Quadrajet problems
« Reply #5 on: May 02, 2010, 04:06:56 pm »
Find out if the core requires a matching number.

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74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline mountaindrew

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Re: Quadrajet problems
« Reply #6 on: May 03, 2010, 12:10:20 am »
http://www.guaranteedcarbs.com/cgi-bin/shopper.cgi?preadd=action&key=CTMHT4663   "...During checkout, there will be a section to enter your number and vehicle information when ordering this remanufactured carburetor. Our staff will use this information to ensure you receive the exact carburetor...."

I guess they want MY carb back.  Maybe now would be a good time to install a Weiand peanut port intake!

1986 Chevrolet C20 Silverado, C6P, 454, TH400, 3.73, FF
oil and trans cooler, 6 qt oil pan, p/w, p/l, air, cruise
17" Dodge wheels & E rated Michelins, Curtis hitch, Prodigy, Equal-i-zer

Offline Captkaos

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Re: Quadrajet problems
« Reply #7 on: May 03, 2010, 10:39:56 am »
I would call and verify.  I have picked up rebuilt ones from local parts stores for luck.