1972 65HP lost power and spark to all plugs

[lesd2009@yahoo.com]

I recently got this 1972, 65hp motor mounted and running on my 1983 16' Bayliner. I have only worked on 3 motors counting this one. I had bought this motor for parts and it turned out I could fix it after rewiring the motor where mice had made the motor home in the field it was left in. I replaced water pump, wires and got the shift solenoids to work with the color coding on them reversed. I reversed the wires on the top of the motor and it shifted fine. Had a carb that was frozen shut on 1st trip but got it working and it ran good the next trip that was about 2 hours. Next trip it was running fine and was cruising the Ohio River in Cincy at a little above idle speed and the motor just quit. I tried and found that it quit firing on all 3 cylinders. I don't have the tool it says to use in the service manual I bought for it to test the coils and CD Pack. Am I going in the right direction and if so, how can I test it with a multi-meter and in-line spark checker?
Thanks for your time in advance.