Spark problem with 1989 120 hp looper when i throttle up

[ICE COP]

Hello all, New to me 120hp looper. 120 compression across all cylinders. According to previous owner engine would not reach full rpm's without dying. I have replace spark plugs,coils,power pack(old one was cracked as if someone had dropped something on it),Regulator/rectifier(I inadvertently removed battery cable while engine was running). Fuel tank is spotless as if new, fuel lines from tank to engine are new 3/8 , new fuel primer bulb and inline filter, new fuel pump with VRO disconnected. Thermostats were rotted and were replaced, fuel is pre-mixed. Since I had exhausted my area of expertise I decided to send the boat to my mechanic with list of symptoms and request to lync and sync as well as set correct timing as previos owner played with every screw and setting. After some troubleshooting tech claimed my new power pack was bad and replaced it, when I recieved boat back I had same symptoms first 10 minutes out, loss of power when attempting to run 3/4 to full throttle then engine coughed and fired erratically. prior to dropping off at mechanics the carburators were also removed and rebuilt using kits and were very clean before rebuild. Motor has been decarbed with seafoam. Power loss seems to be on #4 cylinder. I would almost prefer to just repace the stator and timing ring at this point but need to know if was taken for a power pack by the mechanic who has always been very honest with any motors of mine he has worked on. I am supposed to be going for a test run with the mechanic and was hoping to have a few correct questions to ask.
FWIW The primer solonoid was also replaced and the quick start feature is working perfectly now. Engine starts as soon as the key is turned and one or two quick pushes on the keychoke gets her running beautifully. Quick start drops out after warm-up and about 8-10 seconds after start when engine is already warm.

Your thoughts would be appreciated,
Thank you, Kevin