Quote:
Originally Posted by shaker455
Can you say again what happens when you unplug a vacuum source when idling?
Idle picks up a lot or no real change?
Do you have a digital tach on your timing light?
You should pull the carb off and make sure choke is fully open and no fast idle contact, make sure idle speed screw is in contact with throttle shaft and look and post a pic of how far open your blades are @ idle.
Don't drill anything at this point, gather calibration sizes like bypass air hole size in base.
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When you set the Idle at 800- 850 RPM, with the vacuum advance connected, and you pull the vacuum advance hose off of the port that is normally a ported source( port that is drivers side of the fuel inlet), the engine will immediatley lose a bunch of RPM and stall, but you can put your finger over that port, and keep it from stalling, the prt definitley has vacuum on it at idle, it will suck your finger to it. If you are fast enough, when it is at low RPM after pulling the vacuum advance hose off, you can slip the vacuum advance hose back on it, and it will stay at a slow idle until the engine is once again rev'd, then it seems to gain enough vacuum back on the port, that it once again pulls the vacuum can, adding timing back, and will regain it's faster 800-850 RPM idle, because it will not drop the vacuum can up at that idle speed, until you pull the hose off again and repeat. Yes, we use a digital Dial back timing light with the tach on it. The Timing light we are using is the Innova Pro 5568 light. We are not running any MSD or CD ignition boxes to cause any interference.