Power trim wires were shorted and after the motor was fully warmed up, throttling up would shut down the engine and of course this was just coming out of the no wake zones. Very hard to find and it still trimmed properly in which I could not believe. I would have to go back to my notes to explain 100 % in detail why & how it caused it but that was the problem. Took most of the day to find the problem.

IMO the jist of it was, power trim wires insulation got thinner as the motor warmed up (heat) causing a real short across in which caused a voltage drop hence shutting down the ecm.

Tps? Maf?

forgot to mention this, MEFI 7 is out on the market. GM will be suggesting its use for all their marine Gen V engine set ups.

I know this is a heist, but for any and all of us still with a mefi 1 on a mpi engine, is there a way to ease into the 21st century or is it basically all or nothing?

Buck - MEFI 1 is old and really nothing special to offer that is worth throwing time and money at it. Also even the fuel injectors that were used back in the 1990's are out dated compared to whats on the market now. If you have the VST set up that makes thing even worse for these marine engines. Merc did not keep the VST set up around for long.

MEFI 1 , 2, 3 is no longer available thru any of the marine OEM's nor thru GM. If I remember correctly MEFI 4 was the start for 02 adaptability so IMO that would be the very least starting point for looking to upgrade as far as controllers goes.

Ok , thats kind of what I thought, so when im ready to upgrade, one the new efi setups and 02 sensors needs to be budgeted in as well. Thanks bup!

Any word on what CANbus protocol this new version is comparable with?