15 replies to this topic

[dklawson]

As mentioned above, the RPM should go up, not down, when the vacuum hose is connected. If you cannot hold a vacuum once you disconnect the tube at the carb and suck on the tube, the diaphragm or a tube connector has split. Being cheap, I would at least try a different piece of tubing directly on the vacuum unit to eliminate the possibility of the problem being in the existing tubing. Tubing costs less than a new vacuum advance unit.