Howard Gem Jap Engine

Hi, My howard won't start, was fine last summer, now it gives an occasional backfire through air cleaner when turned over.  Seems to be no resistance when cranking the engine, did a compression test on the cylinder and registered 0.
Any advice would be appreciated,

Thanks, Danny

Yup, like what he smud6ie said.

Hi guys, I just got round to checking the valves and they are functioning just fine.  There is a small amount of oil on one side of the piston, the bore looks okay.  Could the decompression be stuck in the engaged position?  I have no idea how the decompression works. I can't find information on the JAP engine.  It's probably not easy to replace this engine so I'll have to do my best, any advice is much appreciated.
thanks, Danny

 Decompession could be stuck open, as you say.

Also, just wondering, should there be a head gasket on these or is paste good enough?
there's no gasket on this.

Do you have access to a leakdown tester?
smud6ie

The best thing to do would be to send the book to John who will scan it and then return it to you.