Do you have a toilet that always seems to be running? This is sometimes caused by a fill valve that has been set too high, which causes the water level to be higher than the overflow tube.
Toilet fill valves control the flow of water from the supply lines to refill the tank between flushes. Fill valves typically come in two types. One contains an arm with a float connected to the top of the valve. The other type contains a floating cylinder that moves up and down the valve body.
All fill valves are adjustable. Some can be adjusted with a screwdriver and some by moving the float up or down manually. Sometimes there is a spindle you can screw up or down to adjust.
If the water level is too low, it may cause a weak or improper flush. You’ll want to check to see that the water fills to the appropriate line in the tank and readjust if needed. Sometimes the fill valve is adjusted too low and the tank does not fill up with enough water. Those same adjustments you made to lower the water level will fill the tank to the correct height for a good flush.
Check to see if there is an adequate water supply to the toilet. Check the outlet on the angle stop to see if it is a ½” iron pipe connection. A toilet flush requires the additional water that enters the tank once the flush begins. When the water supply lines are too small, they restrict new water from entering the tank fast enough to aid in the flush.
Finally, sometimes the toilet starts to flush but during the process it stops suddenly when a flapper valve reseals onto the flush valve seat. If this happens, usually the flapper valve is not buoyant long enough during the flushing process. Replacing the flapper valve should fix the problem.
Sometimes after all of the adjusting that you can do, you still have a flush that is not strong enough to clean the bowl. Try this. Pour a five gallon pail of hot water into the toilet bowl. Add some Drano. Then go to the water tank and add some Dawn dish washing liquid into the fill valve. Let it sit for 5 to 10 minutes and flush. If it is still too weak, you may have to do it again.