Toilet not flushing??

We have two bathrooms in our home. One half bath downstairs in which the toilet always flushes. The toilet upstairs in the full bath does not complete a flush - I would say - upwards of 75% of the time. It is not being asked to flush an unusual amount of stuff - sometimes it's just a small amount of paper. I am at a loss as to what the problem is. I'm thinking maybe that the vent stack might be obstructed? The two bathrooms do not share the same vent stack. I do noticed that fairly often, if you continue to operate the flush lever while the upstairs toilet is in the process of flushing, it will flush completely - if that is any help in diagnosing the problem. Does anyone have any idea of what the problem might be? I have been living with this problem for years. My main concern is when we have company overnight. This bathroom is just outside of the guest room and is obviously the one that they would use and I would hate for them to not be able to completely flush. I appreciate any help on this matter. Thanks.

The vent won't cause those symptoms. It is more likely either something is trapped in the toilet, the wrong flapper is installed (so it stops before the design amount of water is dropped), the level in the tank is too low, or it's a lousy toilet.

What brand and model is it? Is the water level within about 1/2-1" from the overflow (or at the marked water height)? If you hold the flush lever to empty the whole tank, does it flush better?

It's an older American Standard toilet.....seafoam green - so that tells you how old it is. I use a FluidMaster setup inside the tank and yes, the water level is up where it should be. The toilet does, at times, flush better if I continue to work the flush lever when it is flushing. I can't imagine anything being stuck in the toilet as we have no little kids in the house - just the wife and I. I appreciate any help!

A droped hair pin, barrette, toothbrush, pencil, cotton swab, all sorts of things can give grief. Some of those older toilets never did flush all that well. If when flushing, if you hold the handle down so the full tank is drained, does it help?

jadnashua said:

A droped hair pin, barrette, toothbrush, pencil, cotton swab, all sorts of things can give grief. Some of those older toilets never did flush all that well. If when flushing, if you hold the handle down so the full tank is drained, does it help?

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Yes, as I have stated, if I continue to hold the handle down while I flush, it often times helps.......but not always.

jadnashua said:

A droped hair pin, barrette, toothbrush, pencil, cotton swab, all sorts of things can give grief.

Click to expand...

If something like this is flushed down, sometimes it gets caught on the outlet of the bowl.
It will allow fluids and sometimes solids to pass but will start to clog up with toilet paper and then the next time you flush it may dislog the paper but next time it will start again.

Your best to remove the toilet and check to see if something is on outlet of the toilet.

You can call a plumber to snake it but sometimes a snake will go past the obstruction so have them use a towel or something to pull it through.