We had to replace bathroom floor and decided to put in a new toilet while we were at it.Old toilet flushed just fine but new toilet fills the bowl to almost overflowing but is slow to drain.Ive read several replies and I don't believe any of them fit our problem.Our toilet doesn't have the hole that helps start the suction action.I read on toilet paper work that this toilet is a low consumption toilet.Have I bought wrong toilet? Water will finally drain but takes a while.Water level in tank correct,I tried holding handle longer but that doesn't help.

Take the toilet back up amd check the drain itself and make sure nothing is in the topilet itself where it goes on the floor. I have istalled a few toilets and a couple had either foam or paper stuck up in the neck of the drain. Most floor waste drains are the same so the toilet should be working fine, Maybe the wax gasket went in crooked and is blocking the drain also.

I agree with Handyman, look for excess wax blocking pipe, you may have to snake pipe.

I have a answer that may "fit yourproblem". In my capacity as shop trouble shooter I began to run into a slew of complaints on our new construction that were just like yours. I knew they all couldn't be " bad toilets" so I went looking for the cause. I found that when installing the new bowl that the wax ring had been forced out into the discharge pipe and blocking the free flow of water. When the water hit it a backpressure was set up preventing the siphon that makes a good flush and the solids just swirled around while the water went slowly down. I had to set up meeting with our plumbers and show them the problem and how to fix it. When you set the bowl, put the wax seal down on the flat side to the closet flange. Then take your hands and bevel the wax seal outward so that when you set a bowl on it the wax is forced out instead of in blocking the flush. The customer complaints stopped and I had less work to do. Try molding the wax seal so it doesn't choke down on the flush. Good luck, Tom