Carburerators are the devil's way of making me drink.
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My 77 CJ7 has run for years without any attention, not that I put any great miles on it. This summer it decided it was going to be difficult, so now I have to remember how a carb works, with very small success.
I took it all apart and cleaned it, and blew out the jets. Put it all back together and tried it, no dice. When I come off of throttle, it dies unless I very carefully feather it down to idle. I'm clueless about what's wrong, and have run out of dead chickens to wave over the necromantic device.
I think it would be less trouble to pull the engine and put in a spare 4.0L I have on the shelf.
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My 77 CJ7 has run for years without any attention, not that I put any great miles on it. This summer it decided it was going to be difficult, so now I have to remember how a carb works, with very small success.
I took it all apart and cleaned it, and blew out the jets. Put it all back together and tried it, no dice. When I come off of throttle, it dies unless I very carefully feather it down to idle. I'm clueless about what's wrong, and have run out of dead chickens to wave over the necromantic device.
I think it would be less trouble to pull the engine and put in a spare 4.0L I have on the shelf.
Hows your anti-stall diaphragm (aka dashpot)? my buddy's old truck kept stalling coming to a stop, that was the issue with his.
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My 77 CJ7 has run for years without any attention, not that I put any great miles on it. This summer it decided it was going to be difficult, so now I have to remember how a carb works, with very small success.
I took it all apart and cleaned it, and blew out the jets. Put it all back together and tried it, no dice. When I come off of throttle, it dies unless I very carefully feather it down to idle. I'm clueless about what's wrong, and have run out of dead chickens to wave over the necromantic device.
I think it would be less trouble to pull the engine and put in a spare 4.0L I have on the shelf.
When you took it apart and cleaned it, did you put a new carb kit into it? People talk lovingly about the older generation of cars, but the thing they skip over is all the wearable parts. As in parts that are fully expected to just wear out and stop working. There's tons of them too in old generation cars!
For your case a carb kit would replace all the gaskets, seals, and give you a new needle and seat. This became a kit because all these parts get old and brittle and wear out. Because the carb is a precise device that depends on the vacuum of the engine to operate, any tiny little gasket leak or poorly closing value causes all manor of performance problems.
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Hows your anti-stall diaphragm (aka dashpot)? my buddy's old truck kept stalling coming to a stop, that was the issue with his.
I don't have one, it's a MC 2150 but it's ran for years without issue. It is an auto so you'd think it would have one. But even just sitting still, it'll snuff itself if I jam the throttle and let it go.
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When you took it apart and cleaned it, did you put a new carb kit into it? People talk lovingly about the older generation of cars, but the thing they skip over is all the wearable parts. As in parts that are fully expected to just wear out and stop working. There's tons of them too in old generation cars!
For your case a carb kit would replace all the gaskets, seals, and give you a new needle and seat. This became a kit because all these parts get old and brittle and wear out. Because the carb is a precise device that depends on the vacuum of the engine to operate, any tiny little gasket leak or poorly closing value causes all manor of performance problems.
I didn't but the carb is pretty low-miles. I might have put 500 miles on it in the 10 years since I replaced the carb. I did blow it all out and cleaned out the float bowl. Maybe I missed blowing something out.
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My 77 CJ7 has run for years without any attention, not that I put any great miles on it. This summer it decided it was going to be difficult, so now I have to remember how a carb works, with very small success.
I took it all apart and cleaned it, and blew out the jets. Put it all back together and tried it, no dice. When I come off of throttle, it dies unless I very carefully feather it down to idle. I'm clueless about what's wrong, and have run out of dead chickens to wave over the necromantic device.
I think it would be less trouble to pull the engine and put in a spare 4.0L I have on the shelf.
I don't have experience with that carb, but two old vehicles: One was some slime goo had clogged one of the small carb holes. Looked like maybe a rubber gasket had reacted to something and liquified and been sucked into the hole. The other car having the issue you mention was actually a faulty EGR valve getting stuck.
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I didn't but the carb is pretty low-miles. I might have put 500 miles on it in the 10 years since I replaced the carb. I did blow it all out and cleaned out the float bowl. Maybe I missed blowing something out.
Even without miles, age can make the seals get brittle. Also, have you checked the idle setting? If it’s misadjusted you can have all sorts of odd behavior.
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Even without miles, age can make the seals get brittle. Also, have you checked the idle setting? If it’s misadjusted you can have all sorts of odd behavior.
Been fiddling with the idle mix adjustment screws a lot. Doesn't seem to make much difference.
Yah, I get that age will do it as well, but really 10 years isn't much for a rebuilt carb unless it was truly subpar materials. But possible I guess.
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Been fiddling with the idle mix adjustment screws a lot. Doesn't seem to make much difference.
Yah, I get that age will do it as well, but really 10 years isn't much for a rebuilt carb unless it was truly subpar materials. But possible I guess.
wrote last edited by [email protected]Been fiddling with the idle mix adjustment screws a lot. Doesn't seem to make much difference.
That's usually a sure sign you still have an obstructed pilot or air jet.
Edit:
So you apparently don't have a pilot jet, it's called an "idle pickup tube" in the diagram below. Make good and sure it and the 2 air bleed passages are clean (there is one pickup tube and 2 air passages per "barrel").
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My 77 CJ7 has run for years without any attention, not that I put any great miles on it. This summer it decided it was going to be difficult, so now I have to remember how a carb works, with very small success.
I took it all apart and cleaned it, and blew out the jets. Put it all back together and tried it, no dice. When I come off of throttle, it dies unless I very carefully feather it down to idle. I'm clueless about what's wrong, and have run out of dead chickens to wave over the necromantic device.
I think it would be less trouble to pull the engine and put in a spare 4.0L I have on the shelf.
I had a pinhole leak in the diaphragm of one of my two Mikuni carb, and my twin cyl bike would act really weird.
In that case, it wouldn't evenly provide power with throttle, but just as telling was when I got going and suddenly let the throttle go, the engine would die.
Point is, look at your rubber, old stuff gets destroyed by ethanol, mileage irrelevant.
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Been fiddling with the idle mix adjustment screws a lot. Doesn't seem to make much difference.
That's usually a sure sign you still have an obstructed pilot or air jet.
Edit:
So you apparently don't have a pilot jet, it's called an "idle pickup tube" in the diagram below. Make good and sure it and the 2 air bleed passages are clean (there is one pickup tube and 2 air passages per "barrel").
That's a very helpful diagram. I was blocking off holes while it hit it with air and trying to figure out what the flow was. I'm going to go over it again with this on hand.
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That's a very helpful diagram. I was blocking off holes while it hit it with air and trying to figure out what the flow was. I'm going to go over it again with this on hand.
Keep in mind that only shows the idle circuit. But that's probably where your problem is. Also double check float height if you haven't.
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Keep in mind that only shows the idle circuit. But that's probably where your problem is. Also double check float height if you haven't.
Float height, you mean? Yah, I did that.
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I didn't but the carb is pretty low-miles. I might have put 500 miles on it in the 10 years since I replaced the carb. I did blow it all out and cleaned out the float bowl. Maybe I missed blowing something out.
wrote last edited by [email protected]Sounds like a vacuum leak if it runs with a wide open throttle, but doesn’t idle. Look at all the hoses attached to the intake manifold below the carb. Also if your brakes feel hard to press it could be a leaking vacuum booster (if it has power brakes).
Usually it’s a missing plug or cracked hose in the vacuum lines. (PCV, distributor advance or brake booster).
Edit: I’m assuming this is a Carter YF/YFA carb.
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Sounds like a vacuum leak if it runs with a wide open throttle, but doesn’t idle. Look at all the hoses attached to the intake manifold below the carb. Also if your brakes feel hard to press it could be a leaking vacuum booster (if it has power brakes).
Usually it’s a missing plug or cracked hose in the vacuum lines. (PCV, distributor advance or brake booster).
Edit: I’m assuming this is a Carter YF/YFA carb.
Vacuum was 19 inches so that seemed ok and I got no stumbles spraying carb cleaner around.
ended up using a mc2100 out of an old Ford pickup in the farms dead car alley and putting a kit in it. Now I have to manually choke it but that's just one less thing I have to investigate when it craters next time.
