try this stuff called Goof Off, its sold in most box stores. If the porch is open your OK if its enclosed make sure you have plenty of ventilation.
A place like Lowe's or Home Depot should have the gallons which run about $25.00
Goof off would need a lot of it and gets glue all gummy,a mess!
Ive done a lot of glue down carpet and vct tile removal and installs and the glue is either dried out or still gummy. The best way to get the stuff off is to use an attachment for a floor buffer that has carbide 'teeth' on it or rent a tool that has the carbide on it. Got to go slow and control the buffer. If it is dry glue it works well, if its gummy it still works but slower. Un fortunately it may not all come up. To remove more try a orbital floor sander with 40-60 grit. DON'T use the sander first,you will gum it up so bad and go thru cases of sandpaper. I think you may wind up painting the floor or use those epoxy floor kits with the vinyl chips for garage floors to camoflage the remaining glue
Just saw your post. Talking to a friend today about the pressure washer he just got. I said "how does it work?" He replied "took all the glue off of the porch that was on from the old carpeting." So.. I'd give that a try if you have access to a pressure washer.