Mecruiser 350 MAG MPI Won't Start

Hello everyone ,

I have a regal boat with a Mercruiser 350 mag MPI . Recently i tried to start the engine but doesn't seem to start . I hear the fuel pump when i turn the ignition on . I changed MAP Sensor , Crankshaft sensor , ignition kit even the ECU unit but doesn't seem to start . It cranks but nothing . The problem i found so far is that sometimes when cranking electricity comes to spark plug and after a few tries nothing .

Have anyone experienced something like that before?

I would appreciate your help.

Thank you in advance.

a serial number would help...they have used a few different ignition systems on "350 MAG MPI's" over the years.

When was the last tuneup?

if there adequate fuel pressure in the rail?

Did the engine ingest water? if yes ,replace the sparkplugs. Those fine wire plugs will fail if water gets to them. MR43LTS work just as good