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Running issue

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bigdaddy13 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bigdaddy13 Quote  Post ReplyReply Direct Link To This Post Topic: Running issue
    Posted: 25 June 2018 at 9:49pm
1947 CJ2a
1955ish Fhead
1904 Holley carb

Symptoms:
Engine idles fine, but when I rev it chokes/coughs.

Hypothesis:
I think I ran the tank low and there might be something gumming up the works.

Reasoning:
I ran the tank a bit low, and was able to spot a few bits of black filmy detritus in the fuel pump.

Actions so far:
Pulled the glass bowl - cleaned the screen.
Blew compressed air, after disconnecting, into the fuel tank to clear that line
Blew compressed air, after disconnecting, into fuel line between pump and carb
Drained fuel looking for gummies

Began to idle much better once I cleaned the fuel pump, but still acts like it's going to quit when I rev it. No other changes other than ancillary parts changes (changed out accelerator pedal. No changes to carb or upstream linkages.

thoughts?

Pull the carb, open the bowl and clean off/check the jet?
Pull the tank, and what? wash it out?

thanks...

Edited by bigdaddy13 - 25 June 2018 at 9:56pm
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bigdaddy13 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bigdaddy13 Quote  Post ReplyReply Direct Link To This Post Posted: 25 June 2018 at 9:50pm
It should be noted this car is a runner/driver. the Fhead is healthy and the Holley carb is recently professionally rebuilt - 20 miles or so.

the fuel is fresh, the plugs are getting 12 volts and it's charging at about 13.0-13.5.

This is a pretty "all of a sudden" issue.
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Mike S View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike S Quote  Post ReplyReply Direct Link To This Post Posted: 25 June 2018 at 10:12pm
The carb is the last thing changed, then? Start there. If it just stumbles when you open the throttle, it may be the vacuum drops too fast due to the carb butterfly opening. I don't know much about Holley 2 barrels, so I am guessing.

A vacuum gauge would tell the story, most likely.
'47 CJ2A -- #114542
Warn FF D41 rear
Lock-Right locker
11" drum brakes
Dual master cylinder
T90C Transmission
16 X 6 Jeep truck wheels
Cooper STT Pro tires
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Cinnabear View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Cinnabear Quote  Post ReplyReply Direct Link To This Post Posted: 26 June 2018 at 1:53am
Man, I just went through this nightmare......one of the issues was a bunch of junk in the fuel line. Buddy took a compressor and blew out the line and a wad of who knows what flew out the end....ran like a champ after that.
1947 CJ-2A Willys
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Bill2A View Drop Down
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Bill2A Quote  Post ReplyReply Direct Link To This Post Posted: 26 June 2018 at 2:00am
The black filmy, stringy stuff could well be from alcohol in the gas.
It breaks down into that stuff after about two weeks.
If you live where you have that and plan to only use your Jeep every so often, there is a product called Stabil to keep the gas usable for up to a year.
You may want to pull the float bowl and check for gunk at the inlet valve.
1946 CJ2A 14098
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bigdaddy13 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bigdaddy13 Quote  Post ReplyReply Direct Link To This Post Posted: 27 June 2018 at 7:18am
System was pretty clean. You’re not gonna believe what i think it ended up being.

Literally a screw loose inside the bowl. Or more accurately put, a fuel fitting...that had worked its way loose and was sitting on the bottom of the bowl. 

Cleaned the entire system - still idled OK, but wouldnt rev well. Pulled the carb, Found the screw loose, reinstalled it and the carb itself, and boom...back to normal. 
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Ol' Unreliable View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ol' Unreliable Quote  Post ReplyReply Direct Link To This Post Posted: 28 June 2018 at 3:39am
I believe it.
There's a reason it's called Ol' Unreliable
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