Low compression cylinders 2 and 3, AR 192

[MiaYam]

Boat has low performance won’t go over 6500 rpm’s mid 30s mph. Last time I was out the temperature warning came on for no apparent reason . No water in oil, spark plugs have carbon fouling. Did a compression test and cylinders 1 and 4 have 115 psi cylinders 2 and 3 90 psi. I didn’t opened up the throttle just ran the motor for 5 min on the hose before performing test, all spark plugs out of the engine. Main concern is the difference in compression and the fact that two adjacent cylinders are lower than the other two. This situation could be signaling bad head gasket between cylinders 2 and 3. Any ideas? Can the head be taken out with the engine in place? Thanks.