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My 80 has the dual throat carb, stock, i think, while leaning over the carb from the passenger side, i looked down the throat while i revved the engine. The drivers' side butterfly valve opened up, but the passengers' side didn't. Is that normal? What is that?

anybody have a clue on this.
i just noticed the same with mine last weekend

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1980 luv sport 4x4 Just a memory now
Frame rusted from the inside. Truck stripped and now looking for a new donor in southern ohio

If it's the same as my Hitachi was, the second barrel is vacuum operated and opens after the primary opens far enough to unlock the linkage of the secondary. Although I got to say the primary on my 80 was the passenger side and the secondary was closest to the valve cover.

No it's not normal for a carb to do this. My 79 had the same problem a few years ago. I got a rebuild kit and rebuilt it, but it only lasted a few months, untill i just had to get a replacement. Another thing i noticed happened on both my 79 , and 80 was that there are two little screws that hold the shaft for the butterfly. they have a tendency to come loose, leaving your butterfly at an angle, which restricts its turning , or opening capabilitys.Possably one of the small screws worked itself loose and entered your carborator.

yeah, the primary opens first, and then after the engine builds up enough vacuum at full throttle, then the secondary kicks in.

My 75 has a single choke, so there is only the one flap. Dunno why they did it like that, but who am I to question it?

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More LUV than one man could ever need - Spread the LUV!
- 1976 Chevy Longbed - Daily Driver
- 1981 Chevy Shortbed 4X4 - Needs Help!
- 1981 Chevy Luv 4X4 - Newly put together

My 75 has a single choke, so there is only the one flap. Dunno why they did it like that, but who am I to question it?

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More LUV than one man could ever need - Spread the LUV!
- 1976 Chevy Longbed - Daily Driver
- 1981 Chevy Shortbed 4X4 - Needs Help!
- 1981 Chevy Luv 4X4 - Newly put together

it only has one choke flap because it only runs on one barrel until the other barrel kicks in, in the higher RPM's. so basically, why would you need a choke at full throttle?

yep thats it, basically the back barrels only open at full throttle.

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1980 chevy luv 4x4 1.8 liter
1979 luv long bed parts truck
1984 2wd isuzu pup parts truck

"A man who says it can't be done shouldn't interrupt a man doing it."

it is called a vacuum secondiary. as your rpm increases, your engine builds vacuum, wich when it gets to a certain level of vacuum, it opens that barrelc making more fuel enter the combustion chamber. John, you prolly had a vacuum secondarie carb, adn then replaced it with a manual secondary carb, like the holley that i have.

On my LUVs, the drivers side hole is the secondary, and the butterfly valve is damn hard to get to move with the truck sitting still just revving it up. You turn the linkage and the passenger side butterfly (primary) opens because it is on the same shaft as the linkage to the cable. The secondary only opens when the vac is right for it at Wide Open Throttle (WOT). It won't open immediately when you crank the linkage, at least not on the trucks I've had with stock carbs. You can reach (painfully) around under the carb and get to the shaft of the secondary and open it by hand, but it would be hard to mistake it for the throttle linkage.

The stock carb has basically round holes (slightly squared off near the top maybe) all the way to the bottom. The most common replacement (weber) has pretty square barrels at the top forming into round holes at the bottom. Another dead giveaway you have an aftermarket carb (and therefore all our comments about stock carbs don't apply) is that it will have an adapter plate between the carb and the intake.

so basically i can squeeze some more power outta that old "shitachi" by rigging that secondary up ?

i don't think that would help any, might even hurt performance. it will open when it needs to, unless something is wrong with your carb.

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1980 chevy luv 4x4 1.8 liter
1979 luv long bed parts truck
1984 2wd isuzu pup parts truck

"A man who says it can't be done shouldn't interrupt a man doing it."

more fuel doesnt mean more power. it would be over fueled because you would be pouring all of this gas into your engine that wouldnt be burning up very fast because it would be at low rpms. it gives you good low end power if you feed it less fuel, that is why it has two barrels and not just one.

My craptachi wouldn't run if I held the butterfly's open. It would sputter and die.

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My carb also does the same thing. That is all part of the coasting richer system. It is run by vaccum. When the engine is coasting, a solenoid energizes, causing more fuel to be drawn out of the float bowl and that second valve to open.

im perty shure the carbs are pregresive. So its function sounds normal.

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1980 LUV 4x4, going under re-construction...