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Dirty carb

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69gladiator View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 69gladiator Quote  Post ReplyReply Direct Link To This Post Topic: Dirty carb
    Posted: Nov/22/2020 at 9:25am
I’m having trouble with the two barrel Holley that my son installed in the 232. Over the past six years it’s been rebuilt three times. The shop who did the last repair said debris in the fuel is the culprit. I run an inline filter with rubber fuel line. The truck ran great for about five hours after the last rebuild. The shop will clean it out again. The owner claims that no amount of filtering will remove the tiny particles. The tank was clean seven years ago when I installed it. I intend to replace the rubber fuel lines and install two in line filters. As an added measure I am going to temporarily run a boat gas tank to see if that helps. Thoughts?
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tyrodtom View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tyrodtom Quote  Post ReplyReply Direct Link To This Post Posted: Nov/22/2020 at 2:01pm
Have you cut any of the filters open to see what they're filling up with ?

How do you know the tank was clean inside when you installed it 7 years ago ?
How did you check it ?

 Even if the tank was perfect inside 7 years ago,  that is a long enough time for it to have got lots of deposits in it now,  if the truck hasn't been driven much .

I work with a guy that has 5 older cars that he tries to keep on the road.
Since he only lives about 8 miles from work,  and that's about the only time he drives them,  he's always seeming to have fuel system problems,  especially the 84 MB diesel.

Drive em often,  or store them properly.


Edited by tyrodtom - Nov/22/2020 at 2:09pm
66 American SW, 66 American 2dr, 82 J10, 70 Hornet, Pound, Va.
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Heavy 488 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Heavy 488 Quote  Post ReplyReply Direct Link To This Post Posted: Nov/22/2020 at 3:47pm
How many filters you stack in line doesn't matter is they don't have a good enough micron rating to do what you want.


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tomj View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Nov/22/2020 at 10:03pm
I'm with Tyrodom. 

But back up waaaay to the beginning -- why is it that you suspect/know that it is dirt in the carb that is the problem? Can you photograph it? What's it look like? It matters what it looks like.

Has this engine every run right? With this carb or any other?

Things can get very weird. Here, what looks like simple rust, also contained some weird crap that melted into the valve stems and bent pushrods. I'm not saying you have this issue; my point only is I wouldn't assume it's one thing or another without a bit of work. https://www.sr-ix.com/AMC/1963-Rambler-American/Gas-tank/

If the bowls have more than a couple random specks in the bottom then OK. But two high-quality fuel filters will catch "reasonable" amounts of crud. BUt if your tank is shedding large amounts of ... whatever then the filter will be full and the bowl will have a layer and....


...how OLD is this carburetor? What PRECISELY is the problem? Throttle shafts wear that no rebuild kit can fix. Venturis, air horns, boosters, passages, etc, can corrode, and carbs are subtle, depend on surface tensions and all sorts of subtleties. 

At some point a carb is too old to rebuild.

Again, not saying any of this is the issue, but I don't think we've got enough information to judge.

Posting photos of the crud, or the carb, or all of it, would help a lot. ANd a lot more background info.

1961 roadster american, 195.6 OHV, T5
1968 american, 199ci, T14
AMC pages: http://www.sr-ix.com/AMC/

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69gladiator View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 69gladiator Quote  Post ReplyReply Direct Link To This Post Posted: Nov/23/2020 at 9:31pm
Yes the truck has run very well. My assumption is that the Holley is quite old. The carb begins not to hold and idle and occasionally floods. I’ve been generally getting about a year out of a rebuild   I’m basing the crud theory on what the rebuild shop said. His premise is that if the truck ran well for a few days then ran poorly, crud built up in the carb again. He advised me to disconnect the fuel line at the carb and look at a sample in a glass jar. I haven’t got around to doing that. I’m not sure that I entirely buy the crud theory. This carb has been rebuilt at least four times. 

What’s a alternative to the Holley that will bolt up easily. 


Edited by 69gladiator - Nov/23/2020 at 9:34pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Heavy 488 Quote  Post ReplyReply Direct Link To This Post Posted: Nov/23/2020 at 9:41pm
If you don't buy what he says , take the carb apart. Need to learn at some point.
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tomj View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Nov/23/2020 at 11:34pm
Yeah, "rebuilt four times" is immediately suspicious. Once is obviously ideal, allowing for misteaks, a second time fixes it. A third time I am immediately suspicious without a deeply satisfying amusing tale. Four times is ... 

It might be time to buy a new one or at least used with credible history. Personally, I stopped using used carbs, and I haven't purchased a usable "rebuilt" in many years. The cores are all old. Other than performance carbs -- which are often botched and ruined by amateurs (LIKE ME IN THE PAST, lol) -- no factory carb has been made for 40 years. 

1961 roadster american, 195.6 OHV, T5
1968 american, 199ci, T14
AMC pages: http://www.sr-ix.com/AMC/

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First_Gear View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote First_Gear Quote  Post ReplyReply Direct Link To This Post Posted: Nov/24/2020 at 2:13am
Why not take her top off and get a good gander.
In the carb I mean. Just take the top piece off, called the air horn, and look into the fuel bowl. Don't even need to remove the carb from the car.

This is what I would do if it was mine anyway. Could be something as simple as water getting into the carb. It sits in the bottom of the float bowl and messes stuff up. Its all just guess work until you take a good look.

TomJ: A full rubber filler neck??!! Now I've seen it all.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 1948kaiser Quote  Post ReplyReply Direct Link To This Post Posted: Nov/24/2020 at 5:53am
how old is the fuel line? may be rusted inside it.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Nov/24/2020 at 10:49pm
Originally posted by First_Gear First_Gear wrote:

Why not take her top off and get a good gander.
In the carb I mean. Just take the top piece off, called the air horn, and look into the fuel bowl. Don't even need to remove the carb from the car.

I second that. Wait, this is a Holley, right? So it's that annoying side-bowl crap. As soon as you pop the cover the gasket shrinks to uselessness. Being sideways it dumps gas all over the place. I won't offer my opinion of the design.

Originally posted by First_Gear First_Gear wrote:

TomJ: A full rubber filler neck??!! Now I've seen it all.

Blame Mr. Nash, he done it, not me. I eventually made and all-steel replacement, and used 6" of actual filler hose to couple to it. PITA.

1961 roadster american, 195.6 OHV, T5
1968 american, 199ci, T14
AMC pages: http://www.sr-ix.com/AMC/

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