not running right

[troublesdad]

Mercruiser Thunderbolt IGGNITION --cylinders 1 & 8 not getting spark-new sensor, plugs, cap, coil, wires, not sure what to do next, the engine ran fine unroll it just wouldn't start, replaced the above items so now it runs but no spark to number one and eight , what's up? Please help if possible. Thank you

 

[makomark]

not sure which sensor you are referring to....does the rotor still have all 8 tabs on the spoked trigger wheel?

not have spark at two of 8 plugs is a bit unusual for a TB system

 

[Bt Doctur]

unless you stuck a 6 cylinder rotor in there