Engine runs rough 12-1400rpm

[Saltshaker]

Motor Idles nice and smooth to 1200rpm. From 12 to 1400rpm it is very rough. After that it smooths out again.
Jon

[Joe-JDC]

Does the exhaust send out black smoke and it sound blubblery, or does it backfire?  If not, then you may need to check the accelerator arm clearance(.015" @ WOT), or the timing movement off idle to make sure it moves as soon as the engine starts to accelerate.  If the timing doesn't move, then you need to check the mechanical advance for movement, or the vacuum pot for a bad diaphragm.  Joe-JDC

[FB]

Jon,
 before or after you found out your getting shocks from your dizzy?

[winr1]

Is it rough if you hold the rpm's between 1200 and 1400 ??

Or, as you go through that rpm ??

When did the condition start ??

What carb, cam, compression ??

Perhaps the idle curcuit is not transitioning to the main curcuit correctly


Ricky.

[Saltshaker]

Had the shock problem for the past yr. as fit the rough problem it happens while cruising or holding the motor in the 12-1400 range in neutral. Car just came back from paint shop and the engine bay was very dirty..
Jon

[Falcon67]

Mark the balancer with a white stripe at your preferred timing.  Put a timing light on the balancer while you gently rev it up and look at how the timing mark moves.  It should move smoothly.  If it jumps around above idle, that's spark scatter - either under the cap or possibly interference with the Pertronics controller in the cap.  Alternately, watch the boosters and make sure they don't start early and "blubber" fuel into the intake.  Too high float level, clogged idle air bypass air bleeds, or some such can cause that.

[FB]

Jon, make sure #7 and #8 wires are not next to each other on your wire loom or anywhere else for that matter

[e philpott]

what power valve are you using ? are the carb transfer slots and throttle blades aligned up decent ?

[Stangman]

Is the whole spark plug wire thing with 7and 8 a thing of the past now that wires have come a long way. The original wires were 7 millimeters I believe. Now with the 8 and if your Doug like 10 millimeters. Don’t really know what he has but they are fat.

[Barry_R]

Alternately, watch the boosters and make sure they don't start early and "blubber" fuel into the intake.  Too high float level, clogged bleeds, or some such can cause that.

Changes in italics - - but I would be looking at this....

[Saltshaker]

Cleaned the carb this morning...running perfect again. I’m amazed how dirty it came back from the body shop...specs of compound inside the carb
Thnx again
Jon

[Falcon67]

Thanks Barry, bleeds is what I meant to say. 

>Is the whole spark plug wire thing with 7 and 8 a thing of the past now

IMHO, no.  Electrical crosstalk is never a thing of the past and with a high power ignition wire routing is just as important or even more so.  I run shielded wire for my mag pickups or triggers. The coil feed wires on my dragster are twisted in the frame rail to reduce chances of interference.  After they leave the rail, they change to shielded wire  all the way to the coil.  If you get crossways with a MSD 7-AL3 it'll knock you back to last week.

[Saltshaker]

Shock issue isn’t solved yet...
Jon

[winr1]

Jon, what is ya shock issue ??

Folks may have not seen



Ricky.

[Saltshaker]

I haven’t got that fixed yet....going to figure it out this wk
Jon