Rough Off Idle

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Original F Engine starts just fine but when I Tried to get into the throttle at all, it would just sputter and die.

I rebuild the carburetor and definitely have fixed part of the problem but I don’t think all of it… I can tell that more fuel’s being delivered now when I get into the throttle but definitely sounds like there’s still a lot of skipping. No muffler on it yet so could it be lack of restriction?

I plan on switching over to a pertronix hall effect ignition system and have the parts but am wondering if I should work out the on throttle issue first. That is unless someone tells me that the points are causing this issue.

Thoughts?
 
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Hope this is the problem….
Looks like a dirt dauber had other plans for the vac supply line. I’ll let y’all know tomorrow…

71762EE7-0814-45CD-8BDA-1B6329F2E782.jpeg
 
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Alright… vacuum tubes cleaned and hooked up. Still skipping though. Here are a few videos for reference. One is a bit of throttle and the other is the timing mark at idle. I’m afraid that my distributor may be the culprit because it seems like the mark is floating a good bit.
Thoughts?



 
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My 2¢…

From the video, first thing I think of is fuel starvation.
I don’t think you’re getting fuel when throttle plates are open. Idle circuit seems to be working. At idle, you don’t need a ton of fuel.

How is your accelerator pump? Do you get a good solid squirt(s)? If not, could be…

Fuel pump
Blocked filter
Float level
Blocked jet

If you get a squirt from the accelerator pump, you may have…

Blocked jet / passage in the venturi.

Pull the carb and blow air or carb cleaner through all passages.

You said you ‘rebuilt’ the carb. From my experience, things can still get clogged up after a rebuild. Just happens sometimes.
 

middlecalf

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Sounds rough at idle, something intermittently missing. Pull each spark plug wire and see if you get a drop in idle (also ground on block to see if your getting spark to that plug). A vacuum gauge will give you lots of insight into problems. Google vacuum gauge and you’ll get several links that point to problems associated with vacuum readings.
 
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I’ll pull’er back off and play around with it a bit. The accelerator pump shaft and rubber plunger that came with the cruisertek kit had clearance between the plunger and carb wall so I went back in with the old leather one.

if it should squirt without fuel pressure (engine off) it definitely doesn’t.

I measured in the float level to the best of my abilities. My bowl sight glass shows fuel right in the middle. Does that sound right?
 

middlecalf

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if it should squirt without fuel pressure (engine off) it definitely doesn’t.

I measured in the float level to the best of my abilities. My bowl sight glass shows fuel right in the middle. Does that sound right?
It should squirt w/o fuel pump pressure, and with your bowl being filled (middle is good) that points to the accelerator pump being bad, or plugged.
 
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if you have tried retarding it with no luck ignore the following.

Ignore the timing light readings fo now.
Rotate the dizzy 10 degrees. Clockwise to retard I think? and start it.
A too far advanced dizzy will often idle fine, but once off idle the mechanical and vac advance will make it chug like a mother.
The bouncing around timing light often means the mechanical advance needs attention. Bad/missing springs..worn bushing. Worn bushing Can also make the points open unevenly/ erratically.
 
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It should squirt w/o fuel pump pressure, and with your bowl being filled (middle is good) that points to the accelerator pump being bad, or plugged.
Keep in mind, the accelerator pump only gives the ‘squirt’ when pedal pressure is applied. Running down the road, fuel is drawn in by vacuum through the Venturi / air horn, not the accelerator pump. If the engine still dies when you hold the throttle open, you still have a fuel delivery issue.

[EDIT]
BTW: you’ll only get a squirt for the accelerator if there is fuel in the bowl. With no fuel pressure, you’ll only get a few squirts before it runs out.
[\EDIT]
 

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