johnsonit 200 hp won't start

[pellt@bellsouth.net]

I have a 1985 Johnson 200hp outboard. It wouldn't run for more than minute then it would quit. I have replaced the starter and solenoid ,powerpack ,coils , plugs and plug wires. I am getting both fuel amd spark to cylinders but still won't start. Since this is my first boat I don't really know much about outboard motors, any help will gratefully excepted.

[boats.net]

Check compression, if has spark and fuel should run if compression is even on all cylinders.

[pellt@bellsouth.net]

check compression

what should the compression be on this motor?

[boats.net]

No more than 15% difference between cylinders.