2 cylinders not firing on suzuki 50, could this be a ECU? Do you have one?

[Skiffmate]

50hp Suzuki 2005, 410 hours. Was having shake at lower RPMs, then would not run even at midRPMs, then would ran as if bad miss. Running fuel out the exhaust unburned.
Fuel system, filters, injectors, spark plugs all replaced (see other post) Pulled plugs and bottom one seemed darker/black as if not burning fuel.
Brought to dealer, they checked it all over and said #1 and #2 cylinder not firing (do cylinders get numbered from the top down or bottom up?) They checked everything and cannot find a reason why. They conclude ECU/computer is bad. They said there are none available in the U.S.

Is there a way to test the 'bad computer' theory?
Can someone show me proper part number for the computer? The online parts diagrams have multiple choices based on models. All know is my silver stamped plate on the block says 2004 but the serial seems to match 2005 in the online look up schematics.

My model is suzuki DF-50 but not sure why some have letters AFTER the 50?

Serial:
05001F-510457

I see some working 'pulls' on ebay for very high price tags but need to be sure they will fit.
Anyone have a known to be good ECU I can buy?

Thanks

[Skiffmate]

Found a used ECU known to be working, gave to boat mechanic. he swapped ECU and the MAP code went away. However it still isn't running right. They have had it for weeks and do not know what to do. What can we do next?