Carb rebuild dificulties (1 Viewer)

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Oct 2, 2015
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Port Orchard, wa
So, I began trying to rebuild a spare carb.

I've had issues with the engine since I've had it, and replaced the original carb with a new amazon cheapo which has been, stable in it's poor performance... Where I previously had different issues every day, all of my problems now are reliable.

And, I'm just scared of rebuilding my original carb. So, I found another one a while back on craiglist to try and rebuild first. (I know there's no really good logic to that, but it's what I'm trying).

Anyhow, top cover came off, all the parts came out. A bit dirty, a tiny bits of corrosion on some little pieces.

But, watching pinhead's carb rebuild videos and reading the diagram, I see the "pump outlet ball and spring" (page 6-11 on the field service manual, step 1 and figure 6-19 and page 6-12), which in pinhead's video he calls the accellerator pump... A metel plunger on top of a spring with a ball underneath it..

Well, apparently it's supposed to just fall out. Should be kinda half way out already, held in by the top plate. Mine won't come out. There are a few scratches on it, like someone else had this issue... But it doesn't move.

Has anyone had this problem before? any suggestions?
 

OhioFJ

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I just went through this. Components in my carb were essentially glued together. I used some pb blaster and gently wiggled until they came loose. I didn't use much force for fear of bending something.
 
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Port Orchard, wa
IMG_20200830_223007.jpg

Supposed to have a little spring and a ball underneath it.

It should just fall out. One of the part to be careful with tipping the body over when separating the top plate.

I can see a few little scratches on it. Possibly someone else attempting rebuilding it and had the same issue and never resolved it. Everything else on the carburetor came apart without much challenge. There was some staining and discoloration, maybe a little rust in the float bowl, but mostly didn't look too bad.

This being rusted in place wouldn't be my first guess.

Is there point that I can blow air up behind it?

My only other thought is to drill a hole in it, get a screw and pry on it.

For now, it's sitting in a can of carb cleaner overnight.
 
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Dec 7, 2004
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I had an idle issue with the john deere mower's carb. So i messed with it, cleaned it with carb cleaner and tweaked some more. After two seasons at it, I gave up up dipped it. I was thinking dirt got in it and these surely would clear my problem. I Still had issues and pretty much figured I needed a new carb. But remembered dipping an echo carb in a baby food jar with sea foam and it ran like a top a year earlier. So I put some foam in the tank and john deere ran with idle issues. It was that simple. That being said give that sea foam stuff a try. Figure a way to keep if from evaporating, use a plug if possible or a plastic bag the whole carb.
 
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NY and AZ
I just rebuilt my 76 carb and the head of that should be smooth. It almost looks as if someone tried to jamb something on the top corner and mashed the corner a bit into the side. The spring is fairly light and wont exert enough pressure to push it up if it was previously bent and someone tried to reinstall or if its seated further down. The inside of my carb had some discoloration but not really that dirty- similar to yours so I dont think its somehow cemented in place.
 
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Jul 31, 2011
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Buena Vista, CO
I just did a similar rebuild and I remember that. I think the factory service manual says there is a little circular gasket that covers that hole. But my carb did not have one. I can’t tell from your photo but is that disk metal or perhaps some type of gasket material? If it’s gasket material, you can try and carefully pry it out. If it’s metal, then it’s the carb part and further soaking is probably the best course of action at this point.
On my carb, there didn’t seem to be a problem that there wasn’t a separate small disc gasket there. The larger top cover gasket seemed to be adequate.
 
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On further inspection of your photo, it does look that could be the metal piece that fits in the hole and covers the spring. And there are several indentations, it appears. The ones at 11 o’clock and 4 o’clock look like they may have distorted the perimeter of that metal plug, causing it to jamb in the hole. If so, soaking it likely won’t get it out. Hmmm, could be tricky.
 

Dizzy

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We have seen that before. Someone staked the part in. If the pump jet works, don't bother pulling it out to clean. If you can't get the pump jet to work, then resort to destructive methods. Do you have access to compressed air?

Don't assume that the carb is the culprit to the engine running bad, but, it likely could be. Most of the original motors have dirty valves, and a few have incorrectly set valve lash, or spark dwell, etc.
 
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Apr 19, 2010
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Colorado
76 FJ-40. Rebuilt carb and also desmogged. Engine idles well but bogs down when accelerating. Then seems to run ok after it gets past the bog. I have not driven since the desmog/carb rebuild. Any ideas how to troubleshoot? Thanks
347F8C52-1F29-4673-B18C-395C811CF60C.jpeg
 

Dizzy

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@randyrothe I have the same problem. It is on a '75. It leans out too much, and I know this by my Air/Fuel readout and O2 sensor behind the header. Also, I'm at altitude, and I have intake deposits. It doesn't do this at all with my Weber, but that carb is too small for what I'm doing. I bet that you are above 5,000' in Colorado? We should start a dedicated thread, with more pics.
 
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Port Orchard, wa
We have seen that before. Someone staked the part in. If the pump jet works, don't bother pulling it out to clean. If you can't get the pump jet to work, then resort to destructive methods. Do you have access to compressed air?

Don't assume that the carb is the culprit to the engine running bad, but, it likely could be. Most of the original motors have dirty valves, and a few have incorrectly set valve lash, or spark dwell, etc.

This carb is new to me, previous owner was kinda vague about why they replaced it and thought it needed a rebuild... So I would have to reassemble to test the pump jet. I assume testing this would be with the carb fully reassembled and the float bowl full of fuel, push the plunger that goes into the cavity next to it down and see if it squirts gas into the primary barrel?

I do have compressed air. I tried blowing up into the brass tube right underneath it, but couldn't really tell if the air I felt was coming up through the main barrel or blowing around this. Either way, it didn't move.
 

Dizzy

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@kerplunk The staked aluminum is a check valve. It allows gas out, only. Fill the bow with gas from a jerry can, and try the pump with the throttle, my guess is that it will squirt. Now, the real problem is that it gets all over the inside of the carb, and not directly on the throttle plate, and into the intake. That is a design weakness, but would not be a problem if all other factors are working in your favor.
 
Joined
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I just did a similar rebuild and I remember that. I think the factory service manual says there is a little circular gasket that covers that hole. But my carb did not have one. I can’t tell from your photo but is that disk metal or perhaps some type of gasket material? If it’s gasket material, you can try and carefully pry it out. If it’s metal, then it’s the carb part and further soaking is probably the best course of action at this point.
On my carb, there didn’t seem to be a problem that there wasn’t a separate small disc gasket there. The larger top cover gasket seemed to be adequate.
this piece (from a different carb):
IMG_20200831_175037.jpg
 

Dizzy

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That spring is kinda crusty. Also, there are a couple of sizes for the balls in the check valves, so don't mix them up. I'll send parts if needed.

Actually, only most of the carb needs to be reassembled to test the pump jet.
 
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super glue a nail head to it that may be enough to get it out

IF that doesn't get it out, how do I clean up superglue?

I'm beginning to think it might be best to just leave it, and reassemble the carb assuming the ball and spring are still in there and working properly.

It's soaking a second night in carb cleaner (was rinsed off and wiped down twice today). While I do have a replacement piece, anything that I do to get the old one out, once started, really has to work or the carb is junked. But as is, it might work just fine.
 
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And my next issue...

There is supposed to be something retaining the other ball under the plunger. When I disassembled it, it looked like something a flat head screwdriver could turn. But, the ball came out, and I have no idea what happened to whatever was holding it in, and can't find a picture or diagram. I'm assuming it's some sort of spring clip that's still in the cavity..

But I can't really see anything down there. (But looking again now, zooming in, I see a little piece of wire that looks like it should be holding the ball down and I probably bent it).
IMG_20200830_111237.jpg
 
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Joined
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It’s small circular flat retaining clip. If you grab it with forceps you turn slightly and it will come out. Hard to see initially. But if the ball came out you likely have it somewhere on the shop floor.
 

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