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Discussion Starter · #1 · (Edited)
I need some help figuring this out.

My Corvette was an inheritance from my grandfather, my mom's dad, when he passed about 2 years ago.

This morning I get a call from my mom (who knows nothing of cars) and asks what carburetor does.

I say "It controls the mix of air and fuel for proper combustion."

She tells me "I was awoken at 3am by the sound of a voice telling me 'his carburetor mixture is wrong'".

Believe what you will. I see this as my grandfather telling me, through my mom, what's wrong with the vette.

Problem is, I don't know exactly what he means or how to fix it.

I'd appreciate any help!

300/350 w/Holley 4bbl
 

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Sound like your grand father is looking after you!

What problems are you having with the car? Does she smell rich like gas, possibly with black sooty smoke or are you having problems with surging and back fires...lean?

Hope its something simple!
Wish my dad would tell me what the car needed....would make diagnosing stuff so much easier!
 

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Fuel mix is controlled in a couple places on a carb. First is the idle fuel mix, it is adjusted by the screws in the carb baseplate in front of the carb. they control hos much gas gets mixed with air on the idle circuit. Its set at idle speed, with a vacuume gauge, adjust SLOWLY no more than 1/8 turn at a time for best idle.
Primary fuel mix is controlled by the combination of Jets and Rods, the rods fit into the jeys, there is a specific taper to each type of rod and a specific diameter to the hole and the shape of the hole in the jet.
Secondary (back side of the carb) works the same way
 

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if the mixture is wrong, it will either be too lean (not enough fuel) , or too rich (too much fuel). if you want to check, take your spark plugs out and look at the end. if it is white, it is too lean. not sure what a rich plug looks like, but maybe black. if you got a new carb out of the box and just put it on, most likely the mixtures will be correct.
 

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Six, re-read his first post-- HE's running a Holley there bro.

The idle mix screws are on either side of the carb. Very small brass colored screws. If it stinks at idle, and is an older Holley that may have had a backfire, it's possible the power valve is done. You need to hook up a vacuum gauge for 2 reasons. First, to adjust the idle mixture to the highest possible reading, and second to figure out what power valve you need. If it idles at 10" of vacuum, then use an 8 power valve for example. The vlave should be 2 numbers less than you idle vacuum. If your idle vacuum is a normal 17-20" then a 10.5 pv will be good.

Alternate way to adjust the mixture (idle) is with the engine off, lightly seat the screws, then back out 1 1/2 turns. Start the engine and turn the screws in or out until you get the best quality idle. Keep the number of turns in or out about the same- adjust them evenly. It's way better to adjust with a gauge.

:cheers:
 

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I need some help figuring this out.

My Corvette was an inheritance from my grandfather, my mom's dad, when he passed about 2 years ago.

This morning I get a call from my mom (who knows nothing of cars) and asks what carburetor does.

I say "It controls the mix of air and fuel for proper combustion."

She tells me "I was awoken at 3am by the sound of a voice telling me 'his carburetor mixture is wrong'".

Believe what you will. I see this as my grandfather telling me, through my mom, what's wrong with the vette.

Problem is, I don't know exactly what he means or how to fix it.

I'd appreciate any help!

300/350 w/Holley 4bbl
Call your Mom at 3AM today. Ask her what stock is hot.:laughing:
 

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I don't think that any of them are hot at the moment. (at least mine are'nt) Lost about 4k this month. Oh well it will bounce back, always does>
 

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Discussion Starter · #10 ·
What problems are you having with the car? Does she smell rich like gas, possibly with black sooty smoke or are you having problems with surging and back fires
Yes, yes, yes and yes. All of the above.

Sorry for the short post to begin with. My keyboard at home is FUBARed.

Anyway, I have all of those problems.

The idle screw I've been adjusting is on the throttle, connected to a spring... tightening increases idle, loosening decreases.


So... what do I do? I'm not incredibly knowledgable about Carbs, so reccomendations like Six's and TimAT's need to be written slowly and in as basic of terminology as possible. :smack



Oh, Enron's a hot stock right now. :devil:
 

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