Re: Help me get newer 3.0 running right!!!
You could try taking the top off the carb in place, but honestly it isn't hard to unbolt it from the manifold and get it on a bench where you can work on it properly. You are sort of nuts to try to do it in situ. To get the throttle links to disconnect you kind of have to do this puzzle move with the top. Do-able in place, I suppose, but easier on the bench. Also take a picture and notes on how the links go together before you take them apart. You might think you will remember, but it can be confusing and easy to get wrong. One of my favorite tricks is to put a bit of tape on one end of one link to mark where it goes and which way around, that at least gets me off on the right foot and the rest sort of falls into place.
My only piece of advice on work to do before removing the carb is to start the cover screws with the carb still on the manifold because you may have to use an impact screwdriver. You don't want to do that on the bench because the throttle butterflies stick out a bit from under the carb body and you could damage them or the shafts the are on. Then you are looking at a new carb.
Sierra makes a very complete rebuild kit. I wouldn't start the job without one in hand. Just a few gaskets may be all you use out of the kit, but when you are in there and find you need to replace that little fiber washer that seals on top of that part "21" or some other teensy bit like the part that goes in the needle and seat assembly that is going to fall out on the ground when you take the top off, or the check ball in the bottom of the accelerator pump well that likes to roll away, it is very comforting to know you have them on hand.
Sierra 18-7098
Check that this is the right kit for your carbs, but I'm pretty sure it is.
The idle circuit is in the venturi assembly thing and also has passages in that part of the carb body as well. You maybe could get the "21" part off and blow some carb cleaner through it, but you would still have to get to the teensy holes in the carb body, specifically the ones that come out underneath the throttle butterfly, and blow them out. No way will you get those cleaned out easily in place. And then if this is the first time the carb has been apart you have to clean up all those sealing surfaces. And do so without dropping bits of old gasket into other important places. Bottom line, don't try to take a shortcut, especially this one because it won't get the job done right and it won't save you much work or time, but it could leave you with a much bigger mess.
When you blow carb cleaner through the various parts be sure to wear saftey glasses or goggles because stuff comes out in unexpected places. The nature of the thing. Lots of passages, and even if you think you know where they go often they are clogged so carb cleaner shoots out in unexpected directions. Ask me how I know....
It will definately NOT clean out the fuel passages by removing the idle air bypass screw and shooting cleaner through that part. That passage is all about air and doesn't connect to the fuel passages.... and frankly isn't that teeny and likley isn't clogged. That "mixture" screw as you refered to it only effects the mixture at idle. The mixture at other throttle settings is set by the main jets, and the idle air bypass screw would have almost no effect on mixture while running at any throttle setting other than idle.
Any instructions that tell you how to work on any carb always clearly emphsize that you should NEVER poke wires or other things into the passages. Usually good advice, but sometimes you just have to. In that case take a few inches of electrical wire like lamp cord. Strip off all the insulation so you have a bundle of very fine copper wires. Take ONE single copper wire strand out of the bundle about the thickness of a single human hair or less.... and put a piece of tape on one end so you have a way to keep track of it. This is now a relatively safe probe to go poking about with, but you didn't hear it from me... if you use a big hunk of wire or a big fat strand or a drill bit or someting and you f--k up your carburator..... tough darts... You have been warned of the risks. Usually stubborn clogs will succumb with a soaking in carb cleaner and some time. Sometimes overnight.
Carb cleaner will make you high as a kite if you are not using it in a well ventilated area. And it will cause liver and brain damage too. Take it seriously and work outside or in your garage with the door open or whatever.
I like to spread out a white terry towel and lay out my parts on that. It makes them easier to see and they don't tend to roll away.
The screws in the cover are different lengths in different holes, and it matters that you get them back to the right spots. Pay attnetion and have a system for taking notes or remembering which one goes where.
Lastly I forgot to mention one other helpful hint: When listening to the engine for the "lean to peak" RPM change I try to concentrate on something other than the exhaust note. The loud "bubba bubba bubba...." of the exhaust note at idle changes very little, but if you ignore the exhaust note and focus your attention on the whirring noise of a bearing or belt or accessory like the alternator you will be able to hear the very subtle changes in RPM. Unless your wife is behind you chattering on her cell phone. Seriously, you have to concentrate, but if you do you will hear the RPM change. Once you "get it" the first time it will be forever easy in the future.
Peter
