Just a couple weeks back I pulled a big, Duuuh! I use my Mity Vac almost daily and have so for many years. Pulled out a saw I just rebuilt and ported, was ready to ship it off, box and stuffing at the ready. Thought I would give it its last go over, clean it up as I had test run it and tuned it. Put in the blockers and test plug and hooked up the vac tool, sum of a beech, wouldn`t hold vac, try pressure and nope wouldn`t hold. What the fark! .started pulling the saw apart, squirting suds all about, pulled the flywheel, clutch and no bubbles anywhere. Stopped,had a coffee and had a light bulb idea from out of right field. I blocked the end of my test hose with my thumb, tried vac, nope won`t hold, pressure neither, dip the hose in the liquid and there were the bubbles!!!!