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Old March 9th, 2016, 01:24 AM
Clarke Clarke is offline
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Join Date: Jan 2013
Location: Eureka Springs, AR
Truck: 1962 1500 Wideside 4 speed (305D / SM-420)
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Default Re: Too much timing?

Quote:
Originally Posted by TJ's GMC View Post
Be sure to post your findings!
Update: I mentioned before that ever since I've had this truck, it doesn't matter if I disconnect the hard vacuum line to my vacuum advance; the timing remains the same and so does the idle.

Thanks to TJ, I decided to investigate instead of ignore it. Anyway, I disconnected the hard line from the back of the carb and hooked up my vacuum pump to the hard line. I tested the vacuum advance several times and obtained consistent readings. At 5 psi, I noticed the rod in the slot starting to move, and it would hold vacuum. At 14 psi, the rod would stop moving, and it would hold vacuum. I could pump it up a little higher, but the rod quit moving after 14 psi.

So I removed the reducer fitting from the back of the carb to inspect and it was clear. I also looked in the hole in the back of the carb with my inspection mirror and there were no obstructions.

Do my test results seem normal? Any suggestions on additional inspections? Maybe I need to dig a little deeper into the distributor? The mechanical advance weights/springs on the top side (under the rotor) are clean and move easily.
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