I suggest reducing your feeding to 2 cups 3 tops a day. Your feeding a good food.
Over feeding wont allow him to digest all of the good, and will run thru his system faster creating the runs.
My dog is a bit younger and almost the same size, and i feed 2 cups a day.
Just want to clear somthen up. Poop #1 is solid then a few minutes later poop 2 is the runs?
If this is the case then im still for lessing the food, but my dog does this occasionally.
The second is often runny because he just pooped, but since hes outside he mine aswell get it all out.
Now if he pooped once, and you took him inside, he wouldnt wine to go back out cause doesnt need to get that last bit out, he just did cause you all were outside. They dont know when they are gonna be out next.
From what ive read and understood form this i dont think there is any illness as the cause.
Lessen the feed and see what happens, if nothing changes, id switch food. Innova is a good food tho, which is why i feel 4 cups is over kill.
When was the last dewormer given?