[tsubaki]

I am not the correct person to advise you but my situation is similar.

At any given time I use 9 different outboards ranging from a 1969 model and all the way up to a 2005 model.

Some have the butterfly choke type, some have the primer pulse type. I have to look and see which type the motor has and operate accordingly.

Don't feel bad, my fathers employer had him go out to his house to see what was wrong with his outboard since he could not get it running.
On several different occasions (without the owner present) he went down to the dock, cranked up the engine, took the boat for a ride and returned to the dock with no problems.

The short story was the owner did not know the primer was in the key switch operation.
My father told him "you should have known it was just you and not the boat since your 15 year old daughter uses it all the time, why didn't you ask her to show you how to operate your boat".