2007 310 v drive Stb motor not getting up to rpms

Good evening all,

Bit of a long one here but I'm losing my mind and would love the forums advice.

Had some cracks in the fiberglass towers in the engine bay that the rudder bar bolts to.
The mechanics removed the Stb motor to get better access to cut out the cracked glass and replace. Upon putting the motor back in the motor will not get above 4k rpm and lags the port motor by 300-400 rpm. No work was done to the motor during removal.

So far the shop has put in new plugs and run it with the computer hooked up. No smoking gun. They stated they want to test compression next and then mentioned "or the prop is wrong" well the prop is the same that it went in with unless they swapped it unintentionally.

I'd be shocked if the motor all of a sudden has no compression in a cylinder when it was fine when it went in to the shop.

Could it be a fuel pump or filter? I'm going to run down and swap the fuel filters just to see but I'm super frustrated at this point. Lost half the season with it in the shop and now this. Open to any other ideas too!

thanks again!
Mike

Mechanic is unable to diagnose? Which CF module do you have? I have the CF3 and when the filters get dirty my boat struggles to get on plane and doesn't hit WOT. When I change the filters it's back to normal.

So far mechanic replaced plugs and that didn't work. Sorry the cf? Unfamiliar with that term.