Rebuilding a carb, how do I get "this" part apart?

Hi all.

I am now working on doing a thorough carb rebuild on a 30 year old car. I want to take out the idle (air bleed?) adjustment screws out so I can make sure those passages are thoroughly cleaned out (I’ll make careful note of their positions before I remove them). But how do you get those little protective metal caps/disks that are pressed into the carb housing out to access the screws? I have a dremel so I guess I could carefully grind/drill them out but was just wondering if there was some other trick I am not thinking of.

thanks in advance!

Asked to have it transferred to GQ.

Thanks. I thought that was were I put it. Obviously the morning coffee hasnt quite kicked in yet :slight_smile:

I think you are talking about those things were put in to prevent the owner from adjusting the air/fuel mix so the car ran smoother, and had worse emissions. To remove them at least on the one I knew about you drilled not in the plug, but the ‘stem’ beneath it sideways. Once you made the hole you pried out the plug from under it.

Yes, those are what I am talking about. I am not quite clear on what you mean by the “stem” though.

This is not the way I did it but it may help you out:
http://forums.ninja250.org/viewtopic.php?p=601198&sid=a52a4a05db2b829bd01f47af1e493ed6

Going back to the way I did it, if you look at picture #4, you can see the ‘stem’ extending out of the carb that contains the cap. The stem (cylinder wall) is what I drilled into, and what the shop manual recommended doing. After making the hole the cap was pried out from underneath.

The official instructions I’ve seen are what kanicbird mentioned, drill a hole into the body of the carb past the cap, so that you can punch (or pry?) the cap out via the hole. This method allows reinstallation of the cap (which I do not recommend). With some carbs, including the one pictured in the link, you can just cut off the portion of the carb body that holds the cap, which is simpler.

While it’s not a bad idea to remove the screw and clean its passage, the main benefit of removing the cap is being able to adjust the screw.

Thanks Kanicbird and GaryT. Not sure which method I’ll try because my carb layout is different from the linked pictures and drilling from the side/underneath looks to be a bit more risky given the design. At least I have two of these carbs so the chances are a bit better than normal that I will have a working one at the end of all this :slight_smile:

Its a bit reassuring to at least not hear any DON"T DO THATs!

Thanks again.

Too late to edit:

If the cap is a steel sheet metal square-cornered “bowl,” trying to drill through it usually doesn’t work, as it’s hardened steel which resists drill bits and tends to get pushed back against the screw, making the job tougher.

If it’s an aluminum disc, it can be drilled and tapped to take a machine screw, and then pulled out via the screw, if it’s not feasible to cut the carb body.

Thanks again. I’ll check on that and consider it as well. Man this carb cleaner/soaker shit is nasty stuff (but not as bad as PB blaster…I think that stuff will give you cancer just looking at it).

Oh, since I am going to rebuild both carbs, is there something I should coat the inside of the spare carb so it stores well? WD40 perhaps? Or some of that Fuel Stabilizer stuff? Or something else?

For a clean, dry carb, nothing is needed. If it’s going to sit in a humid environment, maybe wrap it in waxed paper or aluminum foil.

During assembly, I like to coat rubber parts (diaphragms, O-rings, etc.) and “paper” gaskets with silicone spray.

Amendment: For a clean, dry carb, nothing is needed nor desired – a coating could gum up over time.

Yeah Gary you are probably right on that one. The one that gets used doesnt need to be coated. The one I don’t use I’ll just clean up and store the parts. I can always run it through the cleaner again if I ever need to use it.

I got those “caps” out. But guess what? They weren’t caps. They were 1/4 inch thick steel plugs. I started drilling into them with a small drill bit and a dremel drill. I kept going deeper and deeper and deeper and finally decided even if I did get through I probably wouldn’t be able to pull them out.

So I went to plan B. Fortunately these access plugs sat in “towers” that extend from the main body of the carb. I took the dremel cutting disk and sliced across the tower (and plug) making a slot and then slowly deepened it. Once I had cut down through the plug it was easy to get the two halfs of the plug out. I also marked the orientation of the screw slots before I touched them. And fortunately they did not seem to be stuck in place (they seemed movable) but I did hit them with some penetrant oil and will let them sit a bit before I try to take them out.

Those factory folks sure didn’t want people messing with those screws :slight_smile:

Of course I can see why. Car people of the early 80’s were still used to cars you adjusted and fiddled with so the temptation to do that was high. But on a car with a working computer and emission control system thats just a way to make things worse. Now that my system no longer works…well, now it makes sense to get in there.

thanks again.

While there were electronic carburetors, they were rare and I believe problematic. The mixture was just set at a level that would give it a leaner mix (and rougher idle), then most people would prefer, the reason was to lower emissions, and the plug was to stop people from adjusting it to run smoother.

So no there was no working computer, and I don’t think it would harm the emissions system but perhaps over time would destroy the catalytic converter.

Well I don’t know about the rare part. This car has one. Its a 2 barrel carb with a throttle body? controlled by the computer to optimize the air/fuel mixture. Problematic is certainly possible, though I must say the whole computer/emissions control/vacuum line nightmare of a system worked for 20 years and over 250,000 miles before it started giving me trouble. Fortunately this car shares much in common with the Jeep’s of that era so I am finding lots of good stuff on the internet from Jeep enthusiasts thats relevant to my car engines systems. The computer in the car would cost 300 dollars for a custom rebuild and takes a month or two. I ain’t forking out that kind of dough (at least not till I get it roadworthy again and drive it for a bit first) Fortunately, I’ve found Jeep info that gives great detail for how to set up the system to run without the computer.

Oh, and boy am I glad I decided to get those screws out. There was a good bit of crud in there. Given how small those passages are it was enough to be a big deal IMO. It will be interestng to see how the carb on the car right now looks in that regard when I take it apart(its really running rough at low RPM…actually it won’t even run at low RPM).

No need to tap. Just use a sheetmetal screw.

You know, if you’re really serious about making this a nice driver, the thing to do is just chuck that old rat’s nest and get yourself a new carb. Specifically, you want a Weber 32/36, which is an awesome replacement carb for smog-era big 4-cylinders and small 6-cylinders. These things are a breeze to tune, will make the car drive better than new and usually give you better mileage to boot. They’re a little pricey for a cheap car (I once bought a car on the basis of "Weber carb, comes with Dodge Colt: $400), but I would definitely rather do that than spend 100’s of dollars trying to fix the ancient smog stuff.

Here’s a kit for a 151-equipped Jeep of that period, which I bet would fit yours too: Carbs Unlimited Weber Carburetor Conversion Kit

Hey GreasyJack. Thanks for that info. I’ll put it on my redneck Ipad (yellow post it notes).

Oh, I am not going to try to resurect the smog/emission system. Or spend any significant money first. Both carbs look to be in good shape besides needing a good cleaning and rebuild. Oh, I got the carb that was on the car off and apart last night. I thought the first one was bit dirty behind the idle screws? Man, this one was PLUGGED with crud behind the screws. And inside the bowl of the carb was about a heaping spoonful of rust, ranging from sand grain sized to tiny grains. And gummy residue throughout the carb. I guess the fuel filter rusted up inside and blew out sending all that shit into the carb. I am amazed it ran even at high RMP. In a way that nasty carb is good news as it is quite likely thats the reason its not running well.

I just want to get it running well enough that it can be driven around. I think I have the info I need to run it properly without any of the smog/emission/computer crap attached. Then I’ll drive it a bit to see if the engine or transmission or differential or other major parts are okay. If they don’t explode or make horrible sounds in the first few thousands of miles they are probably good for a good while. Once I feel a little more confident I’ll consider getting a good carb like you recommended for the car.

Thanks again for the input

Just an update guys. Got both carbs apart without any major disaster this weekend. Took some serious soaking, rinsing, scrubbing, and repeating. But I was very happy how clean I got em. Some parts on each were broken or worn so I had to combine the best of both to get one good one. I can fix those parts later to have another good carb when I have more time. Put the carb on last evening. The engine ran sooo very much better. Started easy and could idle at 700 RPM without much trouble. Before it ran like a dog and needed nearly 2000 RPM to keep from dieing. When I actually go from redneck rigged to just temporarily run to everything properly in its place and carefully adjusted it might just purr like a kitten. Hurray!

Oh, a funny part. I was using some really nasty carb soaker. Decided I did not want that stuff on my hands, so I put on some heavy duty rubber gloves. They were smidge snug. That soaker was also kinda slick and oily. Well, that meant I couldnt pull them off. I was laughing for a few minutes till I figured out a way to get em off.

Thanks again guys.