Hi Folks. I'm looking for advise on finding a mechanic who knows the Mercruiser MPI systems with Cool fuel.
I have replaced ALL the sensors on the engine. New injectors, Fuel pump & Regulator, Cap,rotor, Plugs & wires
I rebuilt a 4 bolt Vortec SBC with Marine Pro Maxx marine heads.
This thing will run fine for a minute the next spewing black smoke. I have a new IAC valve on the way.
I am in Northwestern Ohio and am willing to drag this thing up to a couple hundred miles in any direction for someone who has the expertise to pin point whats going (not just throw more parts at it).
I have been reading any threads I can find on this MPI & had this thing in many shops for the last 2 seasons so that's when I rebuilt the engine myself due to the last rebuild from a performance shop locally was a flop due to a cracked #7 cylinder. PLEASE HELP!!!!!!

I found the mechanic who the other mechanics go to! Miami Valley Marine in Dayton Ohio, his name is Eddie.
MPI issues 1- Replace fuel lines older than 10 years as they will collapse with the high pressure demand on the inside of the lines!
2- Replace the small white (mesh net) filter in the throttle body throat. It's also called a muffler.
3- Change the IAC, (Control idle air valve) & keep a new spare in water/air tight bag in the boat.
4- Check the distributor timing advance operation.
None of these will set off a error code when they are malfunctioning!
Happy boating all!!!!!!!!!