Can you feel the Allen wrench making its way into the adjuster? It's probably pretty deep into the chamber, about midway, where the diaphragm would be. The function of the adjuster will be to limit the total travel of the advance unit to set how much vacuum advance you get. The only time there would be much resistance to turning would be when the travel is bottomed out, engine running and vacuum applied. At that point, the adjuster won't be accessible because the vacuum line will be attached.

Try checking the advance with a delay-flash timing light at 2,000 RPM with the advance disconnected, then connected. The difference in timing will be how much the vacuum advance moves. Adjust it up or down for best performance and fuel economy. Most vacuum chambers advance the timing 8-10 degrees at light-throttle cruise. Don't exceed about 40-42 degrees total advance with initial, centrifugal, and vacuum all maxed out.
Jerry

Last edited by Hotrod Lincoln; 08/20/2010 1:19 PM.
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