"Jack" wrote:

Here are the symptoms...Flushing the toilet seems to fill the bowl, which
raises the water level in the bowl, there is a small delay, then a flush
which is not very powerful. Water pressure in my area is not great. There
is no clog in the pipe.

Fill a 5 gal bucket with water and pour it quickly into the bowl. If you get a
sarisfactory "swoosh" as the bowl empties, you don't have a drain issue.

Water pressure is immaterial - the flush comes from the storage tank. Pressure
just affects the refill time.

Builder special toilets are notorious for pour hydraulics. I have a couple of
Sterling's (made by Kohler) left that are horrible. Replaced 2 of them with
Kohler Wellworth Lights that work fine. If you want to replace it, pick up a
copy of the latest Maximum Performance Test of low flow toilets he

http://www.cwwa.ca/home_e.asp

Look for the link that says "6 Litre Toilets" and then click on the 8th edition
report.