I have a wc that will not produce the siphon action necessary to flush properly. The water will not overfow the bowl but will gradually run out the trap. The tank water level is where it should be ( this is an older model, 3 gal flush ) and even when allowing the tank to completely drain out while holding up the flap there is still no siphon action. I have taken up the bowl and inspected it closely finding no problem, ran a garden hose completely through the trap and nothing appears to be inside the trap or waterway. The waste stack takes all the water without backup when the bowl is up and poured a five gallon bucket of water down. There appears to be no venting problem in the house either. All I can think of is that there may be some sort of mineral build up in the trap over the years and the bowl needs replacing. Any ideas much appreciated.
1- Have a plumber Auger the toilet for a possible obstruction like “Q” tips
2- Recheck your vent
3- Pour 5 gallons of water directly into the bowl and look for a vortex
4- Reach under the bowl top (where the seat fits) and make sure the holes are completly open and not blocked with lime or other mineral deposits ( you can hold the bottom hole closed forcing the water to shoot out of the upper most holes)