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Old 04-20-2016, 08:20 PM   #1
chefk85
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Carburetor Overflowing!

I rebuilt the old quadrajet today and after installing it into the truck I have an overflow problem. I'm assuming I set the float wrong or possibly having needle seat issues. I cannot for the life of me find the correct float specs. when I look up the carb number it says 74-77 trucks and there are differences in float height. So I set it at 11/32 as it was the most common. The engine is a 283 but I'm setting it for a 350(not sure this matters a whole lot). On my way back out to reset the float height and inspect needle/seat. I did find a few interesting things in the carb as I was rebuilding. First there were two check balls in the carb. I'm sure theres only supposed to be one. Also seems the PO got the wrong carb kit as the gaskets did not match up with carb passages. Hoping that after I correct fuel issue it will run and not bog. If anyone has had this issue and I'm missing something please let me know.

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Old 04-20-2016, 10:06 PM   #2
truckster
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Re: Carburetor Overflowing!

You're on the right track. If you have fuel flowing out of the carb it has to be the float or the needle and seat. The difference in float height is minimal if I remember; most of them are 11/32 or 3/16. Make sure the spring on the needle is installed correctly on the float.
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Old 04-20-2016, 10:25 PM   #3
geezer#99
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Re: Carburetor Overflowing!

X2 on the spring clip.
Info here on that.
http://www.crankshaftcoalition.com/w...4MV_carburetor
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Old 04-22-2016, 08:18 AM   #4
snipescastle2
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Talking Re: Carburetor Overflowing!

quadrajet carbs always had a "Bog" when the secondaries open, but there is an adjustment that you can do to make this minimal. when you disassemble the carb, the upper piece or "air horn" there is a small socket head screw near the secondary throttle blades, I believe you turn it counter clockwise to make the secondaries open sooner...I'm sure somebody will correct me if I'm wrong, but that is one way to adjust the bog factor....I also know there are kits with different metering rods, etc.. that you can "Fine Tune" one of these Rochester carbs....good luck!
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Old 04-22-2016, 10:11 AM   #5
Ft.ValloniaStreaker
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Re: Carburetor Overflowing!

just a easy to overlook idea.....how long is the bolt you used for your air cleaner? If you thread in in to far you'll get an overflow for sure.
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Old 04-22-2016, 12:02 PM   #6
DBK81
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Re: Carburetor Overflowing!

Start by taking the float bowl site bolt out (assuming there is one) if fuel is coming out in anything more than a very very very slight trickle, then your floats need adjusting, if you are good there, but have gas running out the top of your carb, good chance you have something in your needle and seat, pull clean and give it a try, best of luck. I just finished dialing in my 750 Edelbrock, metering rod's springs, accelarator pump adjustments, it's a great feeling when you get everything dialed.
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Old 04-22-2016, 07:19 PM   #7
mMad Dawg
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Re: Carburetor Overflowing!

What kind of float are you using? If it's a plastic one do yourself a favor and replace it. They tend to get saturated and dont float like they are supposed to.If you can find a brass replacement buy it, otherwise replace it with a new plastic one. I think that should solve your problem. Good Luck.
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