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[C1] Engine sputtering on sharp decline

Old Jul 28, 2016 | 05:16 PM
  #21  
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Originally Posted by Frankie the Fink
Well then, a few things:

Float height and a PRECISE positioning of the float in the bowl is hyper-critical on these carbs so I hope your rebuilder was savvy on those points. There is a "left turn stall" fix that has been a known problem in these carbs for years. Fuel can slosh over into a passage and essentially flood the car to the near stalling point.

Its a simple fix but generally the issue only occurs on left turns but any inclines can exaggerate it...
So, to answer your question, yes the stumbling could easily be a flooding condition, in fact, I would give that a high probability.
My mechanic drove it today, was able to replicate the stall at the stop sign but started up right away by just hitting the gas. So he thinks it was likely starving vs. flooding. Will have the guy who rebuilt the carbs have another think on the float adjustment, thanks to your advice. Much appreciated.
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Old Jul 28, 2016 | 05:59 PM
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Well I'll have to defer to 'the boots on the ground'....much easier to diagnose something when you're right there than through cyberspace!
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Old Jul 28, 2016 | 06:09 PM
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Originally Posted by Frankie the Fink
Well I'll have to defer to 'the boots on the ground'....much easier to diagnose something when you're right there than through cyberspace!
So you're not going to help me out with this rash then, huh?
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Old Jul 29, 2016 | 07:26 AM
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Originally Posted by ASJ1960
So you're not going to help me out with this rash then, huh?
Uh...that would be an emphatic NO!
Here is the left turn stall fix - but it may not apply to your situation.
Last pic is one of my carbs with the fix (red circle) - at one point I had 8 WCFBs on cars and as spares and they all had this fix.

A 1/2" of 1/8" OD pipe from Ace Hardware slightly beveled on one end with a jeweler's file for smooth insertion and tapping the piece in the hole slightly is all it takes. I've done it with the carb still on the car at times
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Last edited by Frankie the Fink; Jul 29, 2016 at 07:30 AM.
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Old Jul 29, 2016 | 10:22 AM
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These are all good suggestions, I want to add something for you to think about. On deceleration, engine vacuum is very high so if you have a over exposed transfer slot because of improper throttle blade position at idle vacuum can pull hard on the slot and create a rich condition.

What do the spark plugs look like, that may indicate if the engine is rich.
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Old Jul 29, 2016 | 12:16 PM
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Originally Posted by Frankie the Fink
Uh...that would be an emphatic NO!
Here is the left turn stall fix - but it may not apply to your situation.
Last pic is one of my carbs with the fix (red circle) - at one point I had 8 WCFBs on cars and as spares and they all had this fix.

A 1/2" of 1/8" OD pipe from Ace Hardware slightly beveled on one end with a jeweler's file for smooth insertion and tapping the piece in the hole slightly is all it takes. I've done it with the carb still on the car at times
Interesting, and even more interesting fix. That has definitely not been an issue for me; just the very specific sharp decline, when I can't provide a little extra gas because I need to decelerate or stop. Without me force feeding the engine in those situations, it loses RPMs and stalls.

Last edited by ASJ1960; Jul 29, 2016 at 12:18 PM.
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Old Jul 29, 2016 | 12:19 PM
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Originally Posted by ASJ1960
Interesting, and even more interesting fix. That has definitely not been an issue for me; just the very specific sharp decline, when I can't provide a little extra gas because I need to decelerate or stop. Without me force feeding the engine in those situations, it loses RPMs and stalls.
Well, its about $2 and 35 minutes to install that tube, but, I agree it may not be your problem. I'm not buying fuel starvation though unless a float is hanging up....there is enough in the bowls when decelerating down an incline to run the car for many, many seconds..
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Old Jul 29, 2016 | 12:24 PM
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Originally Posted by Frankie the Fink
Well, its about $2 and 35 minutes to install that tube, but, I agree it may not be your problem. I'm not buying fuel starvation though unless a float is hanging up....there is enough in the bowls when decelerating down an incline to run the car for many, many seconds..
From the little I know--most of which has been provided by helpful souls such as yourself--the float seems to be the thing to focus on. I understand that you wouldn't run out of fuel that quickly if it was a problem with the uptake from the fuel tank, or anything else along the way. If I'm running low on fuel that quickly, it has to be fuel that was already VERY close to getting into the engine.
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