Not sure how to respond to that. First, there is no rubber gasket associated with the head. The 160 uses a brass head gasket / shim but no rubber parts. A loose head can cause serious damage to an engine as it can seriously overheat causing damage to the piston / cylinder / ring. Usually if a head gets loose at all, the engine will just not run but I have seen heads come loose in flight causing serious damage. Now maybe you're talking about the backplate as it uses a small diameter "O" ring to seal it. This plate is retained by (4) screws. Is this the part you are calling the head? If this were loose, it could certainly cause the engine to just stop plus a whole bunch of other problems. If the "O" ring is in place and in good condition, there should be no leak at this joint. If loose, you would certainly see fuel coming from the mating surfaces.