Incomplete toilet flush

[ynotflow]

I have a 40-year old Eljer toilet. It's worked well, with new fill and flush valves about every 10 years. For a few months now, it has not been flushing completely all the time. It would start to flush, but the cyclonic action stopped halfway thru. I replaced the fill-flush valves with a Korky Platinum model, but the problem remains.

I'm beginning to think that 1) an object fell into it and is now lodged in the trap, or 2) the under-rim holes are plugged.. How likely are these?

During the winter, we are often gone for a month, but I don't think that could be a problem, since it worked when we returned. Also, we have a second identical Eljer and it hasn't had this problem; the fill-flush valves have also been replaced as needed.

Any advice would be welcomed.

Thanks

 

[WorthFlorida]

Pul the toilet.
An old story, July 3, 1960 my father removed the only toilet in the house before twenty odd relatives be over for July 4th. Found a metal ant trap in the toilet trap. My two year old sister did it.
Ten years ago working at my church, I pulled a toilet, some kid dropped a scented hockey puck from the urinal. Drives you crazy, sometimes it flushes, other times no.