As Chris said, I would check for a stuck valve and there is an easy test. Pull all the spark plugs and put your thumb over the first plug hole while someone turns the engine over. You should feel the suction of intake and then the push of exhaust if the valves are working. Do this for each cylinder.  It isnt as good as using gauges, but it is simple and will give you at least some indication of one thing that could be eliminated.
                       Cal