Seems to me with all this modern technology there has to be a way to run a closed loop EFI marine system. Will a MEFI 3 or 4 support it? If we take measures to minimalism reversion what are the best ways to do it? Are there different O2 sensor materials or maybe EGTs are more resistant to moisture and a better way to go? With all the great minds here on OSO there has to be a way

As for mefi3&4 i dont think they support it,,as for 02 sensor location if you put the o2 sensor far enough away from where the water blends with water in the riser you shouldnt have any issues,,theirs other places to plump o2 sensors which ive been toying with and when the day comes that i perfected it i will let the board know

call msd,they have a new mefi4 with the software that will plug into the merc harness,that may be somthing for you to look into..

MEFI 4B supports narrow and wideband closed loop.
Works great for a marine app.

Jeff

i spoke to msd ignition and they sold the mefi4 to painless wireing...their version will support a o2 sensor and also has a booste retard with the rite map sensor it will make the proped adjustments..

I have a Holley MPI kit with wideband O2 that I run in closed loop. I set my own targets, fuel and timing map. I have bungs welded in the elbo's on my long risers.