I'm rebuilding a non-starting MS192TC with 150+ compression and spark. Set the carb aside to check crankcase integrity. Would not hold vacuum and leaked pressure around the seals. I put some Dirko around the outer edge of the seals and later repeated the pressure test to see if anything else showed up. To my surprise, bubbles formed all along both flat mating surfaces of the pan and cylinder. When I got the pan off, the pattern of sealant (looked like red Dirko) covering the sealing area showed no gaps. The bolts had been tight. Is this unusual, or does the sealant just break down over time? I plan to use red Dirko (and new seals) when I reassemble. At the risk of starting a sealant war, should I use something else?