I picked up a Mercury 2 cycle Electronic Fuel Injection tester recently at an auction. These things are hard to come by and not sold to the public. If any of the Classic Aquasport membership would like to borrow/use it, I will make it available to you.
This unit plugs into the EFI harness and allows you to test the ECU and other aspects of the EFI system. You can't run these tests without the special Mercury tester:
If you want to borrow this tester, send me a PM and we can work out the details.