96 25hp running on one cyl

[varian]

recently acquired a very lightly used 1996 25hp elect start. been setting for about 6 years, humid climate, motor will run but only on the bottom cyl. compression on both cyl about 115 psi, both cyl getting spark, changed plugs between cyl. if you bring the engine rpms to about 2000 the top cyl will fire periodically. single carb so im thinking each cyl should be running equally good or bad if carb problem. im thinking maybe stuck reed valves. anybody have an idea to help thanks.

[boats.net]

Do a spark test, the ignition should jump a 7/16 inch air gap at spark plug wire on both cylinders. Check for intake air leaks, bad intake gaskets or could be bad reed valves rarely fail.