Redmax EBZ 8500 leaking from crank gasket.

I have had two of my Redmax ebz8500 blowers develop leaks at the crank gasket. My dealer warrantied the short blocks and swapped them out with new ones but about 1 1/2 years later they are leaking again and out of warranty. Is it possible to replace just the crank gasket and have the unit work fine or is the short block a lost cause once you break it down?

If you do break the engine down are there parts that must be replaced with new ones before reassembling?