Carb Vacuum

[Xstream_1]

I was tinkering with my timing today and decided to check the vacuum on the carb. I know that the ported vacuum connection should only have vacuum while under throttle but when I hook the gauge to it I get no reading at all under any RPM. I have a 625 cfm BG Road Demon. My question is shouldn't I be getting some kind of reading at this port?
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[dgc333]

If you are reving the engine in idle the manifold vacuum will be close to zero hence no reading. Hook up your vacuum gauge and take the car for a drive and you should see vacuum.

 

[Xstream_1]

Thanks,
I'l try that tonight. I also spoke with the tech at Barry Grant this morning and he seems to think there may be something plugging the port.

 

[moper]

You should have a reading if the throtle gets openned more than about 1/3. If you snap the throttle by hand, you should see vaccum at that port. It gets lower at WOT, but never gets to 0. If it really got to 0, the carb would stop functioning. The only thing plugging that port, would be the failure of BG to drill it fully. Which wouldnt surprise me at all.

 

[Xstream_1]

You should have a reading if the throtle gets openned more than about 1/3. If you snap the throttle by hand, you should see vaccum at that port. It gets lower at WOT, but never gets to 0. If it really got to 0, the carb would stop functioning. The only thing plugging that port, would be the failure of BG to drill it fully. Which wouldnt surprise me at all.

Thanks guys! I found the problem. I removed the carb last night and found a hunk of red lock-tite stopping the port up. Evidently when they (BG) installed the vacuum nipple they used the lock-tite to hold it in and got a little over zealous with the amount! Thanks for the replies.

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