Blowing Bubbles Here's a quick, easy, and inexpensive way to find an external vacuum leak: First, use a mechanic's stethoscope (just the hose, no steel probe) to try to localize the leak with the engine running. Check the carb base, body, hoses, or what have you. Turn the engine off, then use a small spray bottle of extra-soapy water to spray the suspected area with a moderate amount of water. Next, find a manifold vacuum port (the brake servo booster hose for example) to apply a small amount of shop air. Apply just enough air pressure to get the soap to bubble. We don't want to ruin any check valves or anything. Seal the carburetor throat(s), then watch for the bubbles. You'll find the precise location of your leak. Todd Schmeltz Integrity Automotive Oak Harbor, Washington Visit our Resource Library for available downloads