revilomd,
Welcome to the forum!
Absolutely, you can use the Y-cable! I have this same setup on my boat.
If you get the chance, take some pictures of your current setup and let us have a look just to make sure you don't have some other issues going on!
Is the foot of the motor or something else blocking it or is it caused by turbulence off the transom from a deep V hull, etc!
Good Luck,
Robert