Author Topic: Ported vacuum not acting ported.  (Read 2432 times)

Offline sixth_sense676

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Ported vacuum not acting ported.
« on: March 30, 2013, 02:19:49 PM »
Having trouble with my ported vacuum. The port is always producing vacuum for some reason. This causes obvious problems for my vacuum advance. How do I fix this/why is it doing this?

Also, when I shut off the engine hazy fumes float up out of the carb. Is this normal?

Offline 429bbf

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Re: Ported vacuum not acting ported.
« Reply #1 on: March 30, 2013, 09:31:41 PM »
do you know what your idle rpms are ? it sounds like your idling to fast and your throttle plates are open to far causing the problem.

Offline Cliff Ruggles

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Re: Ported vacuum not acting ported.
« Reply #2 on: March 31, 2013, 03:19:40 AM »
What is the carburetor number?

What is it being used on?

What have you done to the carburetor?


.....Cliff

Offline sixth_sense676

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Re: Ported vacuum not acting ported.
« Reply #3 on: April 02, 2013, 06:31:45 PM »
Carb# 17058253

9.1:1 C.R. Pontiac 350 XE262Cam

Idle @ 900RPM, though at 500rpm the port was still open.

I rebuilt the carb with a HP kit and recipe #1.

Offline Cliff Ruggles

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Re: Ported vacuum not acting ported.
« Reply #4 on: April 03, 2013, 05:08:59 AM »
Most likely needs more idle fuel and idle bypass air.  Recipe #1 is not enough for that engine/cam combination....IMHO