What do you think ? Carb Questions

[Wrecker]

I'd try adjusting it out first. There isn't a lot too it. Just remember where it is so you can go back if needed. Count the turns, etc. Check the exhaust for rats nest too. I had the cat on my 97 clog up and turn the vortec into a dog at any kind of acceleration. You might want to check the timing too. The smoke might be from unbrned fuel due to the engine stalling a little due to bad timing or a vacuum leak. Does it have an emission canister? Probably not being a 76 but I had an 84 Blazer run rich when the valve in the canister broke allowing it to suck extra fuel in that way. (Note, when swapping the engine, don't stand on that canister)

 

[76chevyC20]

PROBLEM SOLVED !!!!! I fell like such a dumb ass. It occured to me that it may not be getting enough air and wondered if the auto-therm on the snout of the air cleaner was not working properly so I just flipped the lid on thte air cleaner. Left for work the next morning and holy crap, the truck ran like a new one. Put the footfeed to the floor and she took off with almost zero hesitation. Also went from using 1/4 tank on my 50 mile round trip to work to about an 1/8th. Now I can get on to other things on my truck. Thanks to all for the info.

 

[HotRodPC]

That's awesome news. Thanks for the update.

 

[Old77]

Awesome!

 

[dhamp]

PROBLEM SOLVED !!!!! I fell like such a dumb ass. It occured to me that it may not be getting enough air and wondered if the auto-therm on the snout of the air cleaner was not working properly so I just flipped the lid on thte air cleaner. Left for work the next morning and holy crap, the truck ran like a new one. Put the footfeed to the floor and she took off with almost zero hesitation. Also went from using 1/4 tank on my 50 mile round trip to work to about an 1/8th. Now I can get on to other things on my truck. Thanks to all for the info.

Autotherm??

 

[HotRodPC]

Thermostatic air cleaner, where the flapper closes off in cold weather to bring air in from the heat riser off the exhaust manifold instead. Its also got a vac pull off to open it if you get on it hard. So it was blocked closed and not opening obviously, and he had a serious rich condition like his choke butterflies were closed which explains the black smoke, bogg and hestation. Makes perfect sense.

 

[crazy4offroad]

Another one of those things to add to the "check the simple **** first" list in my head. I guess I wasn't thinking about a factory air cleaner, not many people run them anymore.

 

[HotRodPC]

Another one of those things to add to the "check the simple **** first" list in my head. I guess I wasn't thinking about a factory air cleaner, not many people run them anymore.

Exactly, and those who do all know of the flip the lid trick, or drill holes around the base of the taller units in like the late 80's style. I'da never thought of that.

 

[dhamp]

Thermostatic air cleaner, where the flapper closes off in cold weather to bring air in from the heat riser off the exhaust manifold instead. Its also got a vac pull off to open it if you get on it hard. So it was blocked closed and not opening obviously, and he had a serious rich condition like his choke butterflies were closed which explains the black smoke, bogg and hestation. Makes perfect sense.

Ahh....thanks for the explanation. Which years/engines used them?

 

[HotRodPC]

Ahh....thanks for the explanation. Which years/engines used them?

All the way up to TBI, so up to 1986. After that, computers and ECMs are able to detect motor temp by water temp sensors and adjust mixtures and timing until motor reaches full operating temp and goes into full closed loop operation at which time, then the motor is tuned for optimal emmissions, mpg and power. That's the way its supposed to work anyway.

 

[wagonman]

Just a little info on secondary opening rates.They can be adjusted to fit your driving style.there is an allenhead screw that holds the sprind tension adjustment and a slotted screw to tension the secondary air valve.Tighter spring =secondarys coming in later.Looser and they come in sooner.Play with it and see what it dose. It wont take much turning to get results. Mark it and go slowly either way. Good for tuning for power or economy...

 

[76chevyC20]

Going to check into that, still could use just a little tuning, but oh how I love the sound of the glasspacks echoing off other cars as I pass them. Probably way more than they do !!

 

[89Suburban]

NO kidding, I got tons of email from subscribed threads and over half of them is 89S eating fuggin popcorn, him and Dave and waving at something.

 

[WHEELMAN]

Some times those..floats.gets..heavy..and when this happens.they need replacing..or they will continue.to hang down and not come up all the way..to shut the gas off..so you are all ways..running rich..i like edlebrock carbs

 

[Don.V]

Just a little info on secondary opening rates.They can be adjusted to fit your driving style.there is an allenhead screw that holds the sprind tension adjustment and a slotted screw to tension the secondary air valve.Tighter spring =secondarys coming in later.Looser and they come in sooner.Play with it and see what it dose. It wont take much turning to get results. Mark it and go slowly either way. Good for tuning for power or economy...

Pics please.