carb removal question (1 Viewer)

[jjhancock]

I'm pulling my 81 fj40 carb and believe I have everything dismantled correctly and the air horn is ready to come off. My problem is that after years of being sandwiched against the gasket and lower assembly of the carb, it doesn't want to budge. I tried to get a razor blade in between the air horn and the gasket but to no avail. I considered a few light taps with a rubber mallet to knock it loose enough for removal, but haven't tried it yet. Does anybody know any tricks do doing this? It's tough to get a good grip on the carb and I certainly don't want to break anything. Any advice would be greatly appreciated. Thanks in advance.

 

[GetsUThere]

I usually just bop it with the handle of a screw driver. If all the screws are out it, it should be fairly easy to break loose.

 

[Pin_Head]

If you are talking about the top cover with the choke plate, it should comre right off with a sharp rap with a screwdriver handle or plastic mallet. If ou are talking about separating the fuel bowl from the throttle body casting, there is a screw that you can only get to frm the bottom side after the carb is removed from the manifold.

 

[jjhancock]

I may have missed something I'm thinking... or not. Are all the screws that need to be removed in order to pull this air horn off on top and viewable from standing above the carb? I'm about 99% sure that I removed anything that was holding it in place, and I definitely removed 7 or so bronze screws with washers from the top plate that seems to mount the air horn to the throttle body casting. Does that sound right?

 

[Poser]

Yep.


Tap it and it should pop loose...

 

[Pin_Head]

I definitely removed 7 or so bronze screws with washers from the top plate that seems to mount the air horn to the throttle body casting. Does that sound right?

It depends on what you are talking about. If you are talking about the top cover (air horn) that has the fuel inlet and choke plate, then there are 6 small screws on the outside and it comes right off.

However, the top cover is mounted on the bowl casting that has the main nozzles. It is the bowl that mounts to the cast iron throttle body, not hte air horn. Since you are having so much trouble getting it off, I thought you might be trying to separate the bowl from the throttle casting.

 

[65swb45]

7 screws from the air horn to the fuel bowl. There should be a notch just below the fuel inlet for a leverage point. If there is excessive resistance [and sometimes there is] use gravity as your friend. Turn the carb upside down and tap on the fuel inlet fitting [harder than the aluminum of the air horn itself]



[NOTE: DO NOT TRY THIS ON AN F ENGINE CARB; they're different!!!!!]

Do NOT jam a screwdriver or anything else between the air horn and the fuel bowl, as there is practically no place [except a small spot on the backside] where you won't mess up a fuel or vacuum seal between the two pieces if you ding the aluminum.

 

[jjhancock]

I may well be resorting to gravity, but I have a question: with the air horn ready to come off (but stuck), can I just go ahead and pull the entire carb off of the intake manifold? I noticed that there are 4 nuts at the base of the throttle body and a thicker gasket separating the throttle body from the intake manifold. Is there anything I'm missing here that would NOT allow me at this point to go ahead and remove the entire carb, or is there more to disconnect that I'm not seeing?

 

[Jukelemon]

Just your linkage and I assume that is off already.

 

[jjhancock]

This thing just won't move. I just spent 20 minutes with a rubber mallet and a screwdriver but it won't budge. Am I a moron? It almost seems as if it's moving some, but I think I'm hallucinating at this point. Is there a solvent I can use possibly on the seam to help get it started?

 

[jjhancock]

It finally moved! I removed it and have pulled the jets. My intention in tearing the carb apart in the first place was to clean the jets (or whatever the brass tubes are called if I'm wrong). I was told that by removing them you could clean them but I'm having trouble seeing how that's to be done. I figure a good soaking in some solvent would do some good, but I'm not 100% convinced. Anybody know a good way to clean these jets?

 

[GetsUThere]

Those long tubes are the slow jets. Unscrew to remove them from the body. The little ones at the bottom of the bowl are the main jets. Both slow and main are different between the primary and secondary side, so don't mix them up when you take them out. The main jets you probably don't need to remove if the bowl isn't full of crud. Soak in carb cleaner and blow out with compressed air I is the generally accepted way of cleaning them unless they're corroded or something.

 

[jjhancock]

After pulling the jets, the slow jets anyway (2 brass screws each jet), it looks pretty clean beneath and I can see the main jets which look ok, if I'm correct and those slow jets are these pictured here: pic

So those are the main jets, or are those butterflies? I'm confused yet again. Either way I've got the removable jets pulled out and soaking in solvent right now. I will hit them with some air tomorrow. If those pictured are the main jets then these: pic 2
must be the slow jets, which are soaking. Thanks again for all your help guys.

 

[GetsUThere]

After pulling the jets, the slow jets anyway (2 brass screws each jet), it looks pretty clean beneath and I can see the main jets which look ok, if I'm correct and those slow jets are these pictured here: pic

So those are the main jets, or are those butterflies? I'm confused yet again. Either way I've got the removable jets pulled out and soaking in solvent right now. I will hit them with some air tomorrow. If those pictured are the main jets then these: pic 2
must be the slow jets, which are soaking. Thanks again for all your help guys.

No, what you've got removed are the venturis. Cleaning them up is a good thing too. Are you rebuilding it or just cleaning? The gasket for the primary looks really ratty. Plus the main gasket looks like it shredded when it came apart... hopefully you've got one. Here's a picture identifying the positions of the jets, which is what you originally asked about.

Edit: you really need a FSM!

Edit again: Now I see where the misunderstanding happened. " I removed it and have pulled the jets. My intention in tearing the carb apart in the first place was to clean the jets (or whatever the brass tubes are called if I'm wrong)." I mistakenly took that to mean the slow jets. Pull one out and you'll see why I thought that's what you were talking about from the description. Sorry man, hope I'm not confusing you more.

 

[Pin_Head]

You should have just said what you were up to. You could have cleaned out the nozzles (aka venturis) and all the other fuel and air ports in the carb just as well as you are doing now without disassembling it. If it is really dirty and plugged inside, regular solvents and spray type carb cleaner just won't cut the mustard. You need carb dip. If you were going to disassemble it as much as you have I would recommend just going ahead and dipping it and installing a rebuild kit and reassembling and adjusting it. That would be a complete rebuild.

 

[jjhancock]

Well, I'm waiting to get my rebuild kit today and am at a sort of crossroads. First off, I don't think I'm competent enough to rebuild this carb myself. I'm in touch with Jim C and he's ready for the carb, which was my intention after learning I didn't know what I was talking about and I'd been given crummy advice from a friend who said he had the exact same hesitation problems as me. So right now I'm torn between trying to get this carb off the intake manifold (which means removing a lot more stuff b/c this is an 81 and those back bolts on the carb are a bitch to get to with all the emissions stuff) and just putting on my new air horn gasket and driving the truck to someplace that can rebuild my carb for me.

One problem here that makes things more difficult is that I'm working on the truck on an RV pad next to my house as my garage is currently unavailable. I figure I'm in it for about the same amount of money regardless of whether I take it someplace local vs. sending to Jim C. The big difference is the frustration and extra time I'm going to have to put in to get the carb completely off and ready to send.

Sorry for vague descriptions earlier in the thread. I really appreciate everyone's advice.

 

[Pin_Head]

You are so far into it that it won't take much to finish it. Take lots of pictures and notes of what goes where. Tag all the vacuum lines, wires and linkage and remove them before removing the carb. Beak it down into the three major pieces: top, bowl and throttle body. Do not remove the butterflies from the shaft and only disconnect one end of the linkage. The less you disassemble it the easier it goes together. Go to your local parts store and get a carb kit and a gallon of Berrymans carb dip. Dip it overnight, rinse it 3x and then blow out all the tiny holes and passages with compressed air or spray type carb cleaner to verify that they are open. Since hesitation is the problem pay attention to the tiny holes at the primary throttle plate and the accelerator pump and its nozzle. Reassemble and adjust as described in the FSM or instructions with the kit. It'll make you feel proud to do it and if you screw up you can put it in a box and send it to Jim.

 

[2badfjs]

another thought justin

you told me the other day that you would get a bucking at hwy speeds.
is you distributor a point ignition or electronic?
if it has points, maybe? could possably be bad points.
i have no idea what dist. is in a 81

good effort on your part to get to know your rig.
keep it up!
we are here to help you brother!!!!!

jim

 

[jjhancock]

Pin_Head,

I was / am seriously considering doing the dip myself and the rebuild. Biggest problem I ran into is that I can't really get to the two back side nuts that bolt the carb to the intake manifold itself. I got to the two on the outside pretty easily, but when I tried to get to the two on the back, I realized I wasn't even getting close to removing them, so that sort of made me give up, temporarily anyway I'll probably start tearing more emissions stuff and the air cleaner tonight and see if I can't get a little bit closer to those bolts and get them broken loose so that I can remove.

With respect to dipping / rebuilding the carb, I'm concerned with even getting the truck to run afterwards considering how finely-tuned this thing (I'm guessing) must need to be in order to function? Am I correct in that assumption, or is it pretty straight forward as to general post-rebuild adjustments that I'm not going to have a major problem?

 

[jjhancock]

Jim, when I pop the dizzy cap I do not see points, ets. IanB from Rising Sun and I talked about it a while back and he confirmed that I've got an electronic ignition. I swear I'm going to figure this out and go wheelin' at least once before it starts snowing!!!