recheck compression,first dry with all plugs out.write down compression 1 thur 6 cyc.then repeat wet.put a few squarts of oil on each cyclinder.if pressure increases after oil (WET).rings are the problem.stay the same valves.Ive always was taught at least 100 lb compression.it may run with low compression but it will be a DOG,no power.how many mi on the engine????.Yes if you have two cyclinders side by side with low comp it;s more than likely a head gasket.Don't press the throttle down.Never heard this done.but I guess i;ll hear a few remarks on that.good luck on your engine.they are a simple engine to work on;not like todays engines,pick up the hood and what the hel# is it
