Help potty training me 11mo dog.

I have a Shih Tzu who seems to only mark outside, never “fully” pee. I take him out four times a day but sometimes he will “fully” pee inside. It often happens when I’m at work but I don’t want to leave him in his crate all day (right now he’s in the crate in the morning, I come home and take him outside during lunch, and then I leave him outside of the crate). I reward him every time he pees outside, even if it’s marking – is this the wrong thing to do?? Please help!