If you can feed oil into the engine's tank using the emergency toggle switch
(key must be ON...) then the problem is with the switch inside the engine's tank.
If you can not fill the engine's tank using the emergency toggle switch then the
problem is with the wiring harness or the remote tank's pump (rare).
Does it transfer oil by using the toggle switch on engine? No oil
will transfer if the yellow oil light in tach is on, if the oil
tank in boat is full and still see yellow light then
oil level sensor on boat oil tank may be bad.