Somewhat guessing but it must be a dirty contact somewhere. Key being on is giving it more power and going down requires less amps than going up.
My motor the relay steals power from the hot side of the starter solenoid. Look at and clean all contacts including ground.
Weird one.
That about does it.....I usually get a long skinny brush and degrease/clean out the tilt tube.
When it's out of the tilt tube try it then....if still hard you will have to purchase a new cable.
Good luck.
I'd say you had a bad switch either internally or on the dash.
The pump should only receive power from one source at a time.
Does the pump have an auto water sensing switch on it or a manual moving switch?
Funny, I have a 77 and the foot is configured like this. I wonder why they used 2 and maybe even 3 during those years. Was a 28 a downsized outboard? Maybe they had lots of gearcase's laying around?
I also wonder if there all interchangeable.
