I sent my ECM off for repair. It was full of water, so far they have not been able to salvage it. The motor is a 350 Mag MPI for an inboard. Is there a big difference between one for an inboard vrs a bravo drive?
Looking up your engine and a comparable sized engine + serial number range, one thing noticed was the fuel injector part numbers are different which helps with the old saying that each engine is specially tuned for fuel mapping and ignition timing. While installing a Bravo ECM may start up and run, without a special engine tuner technician connected to the/your engine monitoring and/or changing the engines mappings, the engine internal components could become compromised.
While your part number is not listed, it might be worth calling Bob to see if he can be of any help. http://obd2allinone.com/mercecms.asp
Who did you send your ECM to? Whipple Marine in Fresno CA, the link above (Bob) or http://simonmotorsports.com/ That says,
ECM555 We can repair most of the problems with these PCM's. Here is a list of things that we fix on a daily basis , water damage , coil drivers , injector drivers , solid alarms , faulty 5 volt signal , or a dead PCM
The Info Below Is Of Mercury Marine Model Numbers Where The Old Engine Control Module Part Number 864299T09 That Fits Your Engine Model Is Used. The New Module Has Superseded To Part Number 864299T10.
Fits 2006-2007 350 Mag MPI Tow Sports (s/n 0W690000-1A299999)
There is something along the lines of 40+ different 555 ECM's. You need to get the correct one for your engine by serial number or else you will have problems.