Mariner 25 hp sometimes no spark

[gbradleyocean]

I purchased a 25 hp Mariner Se

I purchased a 25 hp Mariner Serial # OB186874. Sometimes spark in cylinder 1 and sometimes spark in cylinder 2 but not simultaneously. can you help me troubleshoot? Thanks.

 

[fastjeff]

Spark box.

Jeff

Spark box.

Jeff