couple questions about my carburetor.

[ivorton74]

(also posted on c10forum.com)

So i've been examining my carb and some things dont look right. First of all it dont look like the secondary flap ever opens. I was told that its vacuum controlled. I want to know why its not opening.
There are some vacuum lines that are plugged up..one on the front and two on the right side of the carb. One's for the egr but and dont know where they're supposed to go so if anyone know plz lemme know.
Another thing is that the linkages on the right side of the carb seem really loose. Am pretty sure they aint supposed to be like that.
Lastly i have no kickdown. I need to know how to adjust the detent cable so if anyone can gimme some pointers it'll be really appreciated. That's all for now.

Here's some pics of my carb...

[K 20 blazer]

On the kick down, A TH 350 uses a cable. A TH 400 uses a switch, and 12 volts.

Some of the linkage parts are a little loose. It depends on which ones they are.

Try to find another carb to compare with.

The secondaries opening depends on the carb.

[donut]

Try again with the pics. What's it on?
Secondaries are vacuum operated (assuming it's a q-jet). When the throttle blades open, the engine vacuum will pull the upper flaps open. Then you'll hear it. Sitting in the driveway, blipping the throttle, you more than likely won't see the secondary flaps open.

[raceman6135]

I don't see any pictures.

We don't know what carburetor you have.

We don't know what transmission you have.

Both K20 & donut have given good info, but we require more from you, ivorton, if you'd like more help.

[ivorton74]

sorry about that guys. its a 74 c10 with a th350 tranny. has a quadrajet 4 barrel carb on it. pics attached.

[Malo83]

Some GUMOUT carb spray wouldn't hurt to clean up the Qjet but it looks like all the linkage is there, how does she run ?

[ivorton74]

she runs ok but lately its been sputtering and idling kinda funny. idle speed will gp up then down again and there is a small popping sound coming from the exhaust. the carb base gasket was leaking so i changed it. its not sputtering as much but its still idling weird. i want to try adjusting the mixture but not sure how to do it. am going to change my plugs and stuff again and see how she runs. i got the truck last year and it was parked for over 5 years so i know there's going to be some issues. tryn to fix it piece by piece. am tryn to get everything working properly.

[Hotrodrobert]

With the choke COMPLETELY OPEN open the throttle wide open. The secondary shaft should rotate about 90 degrees. If not, the shaft is stuck and you probably have other issues with how dirty the carb is.
With the air filter removed, push on the rear of the secondary air flap. It should have some resistance due to the spring holding it closed but should not bind or stick.
Have someone push the throttle to the floor and be sure the carb actually gets WOT.
No kickdown is cable adjustment or tranny trouble. The cable looks right, hooked up correctly, etc.

[donut]

First thing I'd do is invest in some carb cleaner, It'll be easier to spot something gummed up if all the linkages are clean. IMO ditch the air cleaner and put the OEM back on. Linkages on the right are mostly for choke operation, they're not real tight anyway. Drivers side, behind the throttle return springs, is your kickdown for tranny. Might need adjusting, might be broken, might be disconnected in trans, cross that bridge later.

Clean it up, do your tune-up, hit local library/bookstore for Haynes/Chilton's manual.
Carb might be gummed up internally, fuel filter/ tank sock might be clogged (esp if it sat 5 years). Vacuum leak, check your caps on vacuum lines. Spray around carb and listen for a change in idle, base gasket may have helped, but may still be leaking. If carb is org, throttle shafts might be worn. Back to the base gasket, is it the correct one? it does make a difference. I was on my 3rd before I got the correct one.

I mention tune-up, what your describing may be an ignition problem.
HEI would be a good upgrade if your to that point.

[powerdriver 1958]

That picture show a points and condenser distributor .When was the last time the Points were adjusted or replaced ?

[ivorton74]

Yeah I really do need to clean it up...it's actually pretty embarrasing...I did give the engine a wash in the summer but ill have to do it again. I dont have my old air cleaner anymore...sold it on ebay. I did some work on it early this year after i finally got the title for it from the p/o...new plugs and wires,new coil,new battery and terminals, new points and condenser(twice), fresh oil, new hoses and belts, front brakes...I just got it out of the shop last week...has had a new 2.5 inch exhaust with thrush turbo muffler put in, new rear main seal, new tranny rear seal, fresh oil, fresh fluid in the rear end and other little things. Me and my uncle adjusted the points a few days ago and its still in good condition but I'm gonna convert to HEI as soon as possible. Just changed fuel filter as well and poured some seafoam in the tank. Used seafoam once before on the truck and it works pretty good.
I plan on switching to a holley street avenger when i get some cash but for now i want to make this carb is working good. And I would like to have kickdown so i can have some passing power. How do I go about adjusting the cable?

here's my truck btw...paid $400 for it. a work slowly in progress.

[Hotrodrobert]

If your Q Jet is close, the poor Holley will use more gas and not make any more if as much power, give a lot more trouble.
Less expensive and just as good if your distributor is in good condition might be a Petronix conversion or some other brand. Had very good results converting points to Petronix.

[Psycho71]

My advice....Get rid of that air cleaner asap. One little burp back thru the carb can spit gas into that foam element and then burn your truck to the ground. Even if that doesn't ever happen, the element will eventually dry out and start to crumble. The pieces will then get sucked into the carb, and engine. Those elements should be outlawed.

If the q-jet is operating close to correct, I'd have to consider servicing it. And that's not easy for me to say as I am one of the first people to toss them in the garbage and put a holley on. A good Holley, with the correct tuning, will make more power, and I've never had problems with my Holleys going out of tune. But there are lovers and haters of everything. And most have good reasons for their likes and dislikes. I will say though, the q-jet having smaller primaries will save you some money at the gas pump. And with fuel prices today, that might be enough to make up your mind.

If nothing else, a good going over with some carb cleaner couldn't hurt that thing either.

[ivorton74]

yeah im think of pulling it off and cleaning up and im gonna get a rebuild kit for it. ill change out this air cleaner for a nice chrome edelbrock round cleaner. plus i want to get that hei distributor from summit.

[motornut]

that little stick keeps the secondarys from coming in while the choke is on
i usally bend that ,even if the choke is working
how is the egr blocked off under the valve
is the vac line from the manifold to the tranny kick down a good seal
make sure the other vac lines are sealed tight,
i'd change what looks like a fuse in one vac line,wouldn't want it breaking

[C-10 simplex]

Originally Posted by Psycho71

My advice....Get rid of that air cleaner asap. One little burp back thru the carb can spit gas into that foam element and then burn your truck to the ground. Even if that doesn't ever happen, the element will eventually dry out and start to crumble. The pieces will then get sucked into the carb, and engine. Those elements should be outlawed.

If the q-jet is operating close to correct, I'd have to consider servicing it. And that's not easy for me to say as I am one of the first people to toss them in the garbage and put a holley on. A good Holley, with the correct tuning, will make more power, and I've never had problems with my Holleys going out of tune. But there are lovers and haters of everything. And most have good reasons for their likes and dislikes. I will say though, the q-jet having smaller primaries will save you some money at the gas pump. And with fuel prices today, that might be enough to make up your mind.

If nothing else, a good going over with some carb cleaner couldn't hurt that thing either.

Exactamundo! Look what happened to me:

http://forum.73-87chevytrucks.com/sm...ic,7169.0.html

The stock assembly is better than you might think. And if you really think you need that much air intake(and i really don't think you do at this point, if i may be so bold), you can always stack 2 on top of each other and get outside, cooler air because you have the ability to use the snorkels.

But the main thing is don't take chances with fire. i think Edelbrock really makes some quality parts, but this is one area where they dropped the ball.

[ivorton74]

Originally Posted by motornut

that little stick keeps the secondarys from coming in while the choke is on
i usally bend that ,even if the choke is working
how is the egr blocked off under the valve
is the vac line from the manifold to the tranny kick down a good seal
make sure the other vac lines are sealed tight,
i'd change what looks like a fuse in one vac line,wouldn't want it breaking

i got the truck like that. all those vacuum lines were blocked of when i got except for the one for the distributor. im tryn to find where they all run to. i bought new vacuum hoses to run them. not sure about the vac line from the manifold to the trans kickdown. will have to check it out.

@c10-simplex...wow i didnt think that aircleaner was that bad. will change it out asap. i dont have the original air cleaner. i bought this one cuz it looked good and was cheap. i guess u really get what u pay for.

[motornut]

the sensor in the thermostat housing may be the one for egr
which would cause the running issues
1.is to the egr
2. is the vac from manifold
best to get a block off plate

the yellow line appears to be a carb leak (you mentioned you fixed),
may want to check the butterfly pivot area on the throttle body
gas can leak/dribble out sides at the green line
(where the little stick is from before)

the tranny kickdown looks ok as long as it dosn't leak (yellow circle)
check the other end tho too

[ivorton74]

@motornut...thats pretty detailed.thanks alot man..thats gonna help me pretty good. but what are those two plugged hose on the carb for?(marked with red arrows in pic)

[motornut]

one would feed the thermostat housing
and the air breather...seem to remember the angled one