If this is the same motor as your other post we need to check that the controls you have are proper for the engine. If so post model number of old engine and model number of new engine. Also post pic of controls, harness plugs, deutch connectors, the shift rod for the other post...etc. people will help but they need the whole story, even if one thinks it may be irrelevant.
Diagnosing from the nets takes answers. I am confidant this can all be solved. There is a lot of experience in these pages
Problem solved... I prepared to pull the wiring harness a to do an inch by inch inspection to try and solve this wiring headache.. I unplugged from the motor and started pulling the wire thru the hull. I had previously untapped and inspected a splice in the harness but when pulling it thru I found another splice, untapped it and found it to be very corroded. re-spliced this and plugged everything back up to try. Motor cranked but when turning the key to off discovered port bank would die but starboard still firing. Replaced the diode in the interrupt switch wiring. Motor now shut starts and shuts off properly. Thanks for every ones help.....