cletus

Ok, a friend and I set out trying to change the carb on my '84. Neither of us have ever messed with a carb before. Amazingly enough, we got it running, but it will not idle. So I have some questions for a bunch of you carb gurus out there. There were some things that I have no idea what they do. Also, they carbs were slightly different models apparently. Some different/missing places for vac tubes, etc. So now I have a couple of questions

In the process of this thing, we yanked out the entire rats nest thing. I'm probably just going to register the car where I don't have to worry about emissions. Besides plugging the vacuum lines that remained in the car, is there anything else I need to do?
The person I got the carb from had it set up without emissions stuff, so everything was plugged. All I hooked up to the carb was the throttle cable ,the 2 oil compensator tubes or whatever, and electrical connector on the primary side of the carb. Is there anything else critical?
What are the little electrical connections on the primary and secondary sides of the carbs at the top? We hooked up the primary one, but the secondary one had the wires cut off. Is this a required thing?

Any suggestion on the idle? Do I just need to play with the idle adjust screw or what?

Thanks for dealing with my retardedness

MIKE-P-28

iTrader: (1)

Theres a plug on there, beleive they call it the carb heater. Its a one pin connector with a thick wire... Yeah id say play with the screw, but if this carb has set for some period of time, it would have been best to open it up, and removed each thing one and a time, cleaned and replaced it to its respective spot..

cletus

Ok, I just want to check some stuff. Which screw is the idle adjust? See the pic for reference, or am I totally in the wrong area looking at these 2 screws?

Also, there is a linkage that has nothing attached to it and I was wondering what it did. I attached a 2nd pic with an arrow pointing at it. Someone know what it does?

Thanks again guys.
You guys rule.

cletus

Here's the 2nd picture.

Richard Miller

I will say that that was the most detailed picture of anything I have ever seen. What camera did you use?

REVHED

The top one is the idle speed screw and the bottom one is the mixture adjustment screw. In addition there is a screw on the linkage that adjusts how much the throttle butterflys are open at idle.

cletus

Ok, I think that 3rd screw is where I need to go. She ran fine if I just kept my foot on the gas a little bit. Someone else mentioned it, but like I said I know nothing about carbs so I didn't really know what they were talking about . I'll look around on one of my spare carbs to find it before I go digging. Thanks.

Also, do I even care about that little thing the red arrow is pointing to or is that something for emissions?

Camera was a kodak dx3600. It seems pretty decent. Haven't had it all that long. It does audio/video as well, but that quality isn't that great, but hey, it was a $300 digital camera. What do you expect.

CrazyJoe12a

On my carb, where the idle adjust screw should be, it has what looks to be an OMP line(yellow/clear plastic tube) The mixture screw is where it should be. It's an 82 chassis but I believe it an 84-85 engine, did they get rid of the idle screw on the later engines, or do I just have a bastard carb??

yayarx7

they made the later carbs non-adjustable

I think the second pick is of the choke rod. it used to have a diaphram attached to it to slow or assist the choke or something like that

cletus

Ahh. Yeah, it used to have a diaphram attached to it I think. Well, this one doesn't have the choke on it, so I could care less if that's it .

yayarx7

no choke but it has the choke rod? I am confused.

Felix Wankel

Did you pull the choke plates off and leave the rod?

Sterling

Either leave the rod, or plug the ends where it was...
Something to remember, Cletus-
Two of the vacuum lines were to go to the distributer vacuum advance pots. These used to be important before you ripped out the rats nest. Now not so much. Optimum timing can be set. Leaving them alone will be fine, just not 'optimal'. BUT- hooking up the wrong vacuum lines will screw with your timing a bit and you'll get a choppy idle as the engine chases its tail (carb vacs the timing, which phases through an ideal, which ups the idle, which changes the vacuum, which changes the timing back, ect).
Do not plug these vacuum pots.

You have a butterfly valve in your 84 intake manifold for decelleration. It sucks, and can complicate things. It also creates a giant flow impedence. Don't worry about trying to get it out right now (do it as part of an "upgrading" later), but make sure it is'nt closed.

The solenoid you describe on the secondary side of the carb is probably part of the altitude compensation system. Don't worry about it.

The different carb models probably have different step-air bleeds, and I imagine the fuel jets and primary bleeds are the same.
The reason I think they have different step bleeds (those are the really short air bleeds that look like fuel jets, and are for idling) is because the emissions control systems changes (albeit very little), but also the fuel pump output changed from year to year.

In order to get my Yaw to idle correctly with my fuel requirements, I had to replace the primary step air bleeds with secondary step air bleeds from another carb (bigger).

I recomend this ONLY when you've exhausted ALL other possibilities. This will be a real pain in the *** for you with a stock lid on your carb body. Take the lid off the other carb (airhorn I mean) and locate the step air bleeds. These are on the outside edges of each row of bleeds and are very short (Not the emulsion tubes with holes in the bottoms).
Be careful of the gasket, floats, ect. Take great care even with the old carb. You never know when you'll need bits from it, or just want to fix it. (They are ALWAYS fixable!)

When you have both carbs apart, you should take out two fuel jets from the fuel bowls, and compare sizes. I think they are the same, but I don't know for sure.
If you find you have four different sizes in your hand, then use the largest for the secondary, and the second smallest for the primary. (obviously do the other side as well.)

But before you go through all this crap, get an assistant to start the engine while it's cold, and spritz LIGHTLY some either around the carb. If there's a leak, it'll get sucked in, and the engine pitch will change.
Be very careful with this stuff. It looks for the opportunity to catch fire!

Your mixture should start all the way turned in, and backed out about 1 3/4- 2 1/4 turns. You set it so it sound the best, reset the idle speed, and then reset the mixture screw again. Back 'n forth until you're idleing at 750-800 RPM, and it sound good with no stutter.

The carb needs to be tuned on a warm engine. Get it tuned on a cold engine perfectly, and as soon as it warms up, everything is off.

cletus

Ok, so I went looking for that elusive third screw that people keep telling me about. So I studied the other carbs I have first and found it. Easy enough. So I went looking for it right in that same place on the carb on the car. Said screw is not there. It's function is obvious now that I have looked at it, to push the primaries open a little bit and basically serve as a stop to keep them from closing completely. So I grabbed the screw off one of my other carbs and tried to put it in. The screw will not fit in that carb. There is some other stuff in the way. Basically it is too long.

So where to proceed from here. I take it that screw is completely necessary. Tell me if I'm wrong. Go to home depot and find a screw that will fit? Or adjust the throttle cable mounting on the carb so it is always slightly kept open?

Thanks for any advice. I wish I had a freakin' clue about what any of this stuff is/does.