Mercruiser 350 MPI
 

Hi,
I am having problems with my Bravo 3 350 mpi. It is sooting up the transom and running very rough after slow trolling. When you throttle on at clears up and runs fine.
Have already replaced ignition module inside distributor and then found coil was not sending strong spark so replaced that as well. Was great for next couple of trips but now doing the same thing again.

Was wondering if it could be a bad coil driver (has been upgraded to mefi 4) that is maybe killing the coil?

I did replace the coil witha factory part not an after market coil.

Motor also stalls if you come off the throttle fast. When the coil was new you could just come off the throttle any way you wanted to and it was fine.

Hope someone can suggest something

James.

sounds like a bad injector. ohm them out, they should read approx 15.7 ohms change out if more than .5 ohms higher or lower.