On Thu, 02 Sep 2010 13:22:46 -0700, TN wrote:

I tried that and it flushes normally. I am not sure I understand, are
you saying the incoming water to the bowl is too slow or there is a clog
down the drain? The incoming water seems to be as fast as the other 2
toilets, but I could be wrong.

So if you flush the toilet with a specific mount of water in a bucket it
flushes ok? On the toilet that flushes ok here is what you do. Get a
bucket and fill it with a little water. If it flushes, fill the bucket
back up with less and less water until it doesn't flush. The aim is to
see how much water is needed to flush no more no less. Now take that
amount to the problem toilet and see if that amount will flush it. If it
does flush with the minimum amount of water from the bucket it took to
flus the good toilet that means the toilet is not supplying adequate
water and you have no blockage in the soil pipe or siphon.