male cat that pees on floor

Question
Hi, I have a stray male cat that has been fixed.  He isn't spraying in my house he just refuses to use the litter box.  I am at my wits end.  I have gone out and bought another litter box so that my cat and this cat will have their own separate boxes and I clean both of them multiple times a day, but it doesn't help.  I take and put him in the box multiple times just to try and get him to go, but he just jumps out.  I have tried locking him up in my bathroom, thinking that he will have a smaller space and maybe it will force him to use the litter box, but then he will just pee in the box and crap on the rug in the bathroom.  I have realized from the past 2 mornings that if he pee's in the box then he craps on the floor, and if he craps in the box then he pee's on the floor, which of course it is always on the carpet or the rug.
Since this is a stray cat, I have not taken him to the vet to even see if he has a uti, because I don't want to spend the money if he isn't going to stop doing this.  The only reason that I ask, is my sister has 3 cats, the mom and 2 son's they have all been fixed, and one of the boy's has always since he was a kitten, has pee'd on the carpet and he has nothing wrong with him, he is just a little pee'er.  Is there anyway at all to break a cat from urinating on the floor?  He will occassionally pee in the box but only when I am forcing him into the litter box multiple times, it't like he gives up and just goes, so that I will stop shoving him in there.

Answer
Hi Debbie, thanks for the question! This type of behaviour is one of the toughest to cure but it sounds like you are up to it !! I am pretty sure this is more behavioral than a UTI.
You were on the right track with putting him into a smaller place.. but you didn't go quite small enough!! :)
The reason he is not using the litterbox is that he does not feel safe in it, probably due to the other cats being around. If he has been a street cat he has learned to not leave yourself vulnerable and you are very vulnerable when using a litter box ! Another reason he doesn't use it is because of habit. This is the easiest to cure. Borrow a large dog kennel and put him in the kennel with a small bowl of food and water on the door and with half the kennel being taken up with the litter box. He will be fine in there for a couple of days and he will be forced to use the litter box. Then put him into the bathroom for the 3rd day with the same litterbox and with no other cats coming and going and no bathroom mats! (I don't know why cats LOVE to pee on them!! I think it is something to do with the rubber backing and that smell!) Then if he is successful in the bathroom leave him there for a week. This will not kill him... haha. IF HE IS NOT successful then put him back into the dog crate for a day again. Do you see where this is going?? It is about developing the habit of always using the litterbox! It can take 2 weeks at least to get this habit ingrained into him but then you should be fine !! Also if there is one particular place that he has accidents, and this is good info for your sister also, clean the area well with a pet odor remover from the pet store and then put a bowl of food down there !! A cat will not soil where he has to eat. Also tin foil is  a great way to keep a cat off the accident area as they hate the feel of it on their feet ! Once your cat has the correct "habit" and is consistently using the litterbox then you need to find a spot that he will not feel vulnerable with the other cats watching him.....
Let me know how you manage! Teresa