In my area, the water is quite hard, which has led to calcium deposits
> in the rim and the siphon jets. Give the toilet a flush with a bucket,
> to check if it'll start siphoning that way, but I suspect your jets may
> have lost their "calibre". You know, atherosclerosis of the porcelain.
> I've heard of folks dissolving the deposits with an acid solution, but
> it was an involved, tedious process. Some think a wire coat hanger,
> bent just so, can auger out the rim jets. I'd probably buy a new
> toilet, a good one. Tom
I tried the bucket of water test, and the toilet worked. I used a copper wire and went through all the "jets", and they seemed open, but how much can you see with a mirror. I raised the water level a bit in the tank, and that made it work better. I also noticed that the water level in the bowl (after a good flush) is too high, so I think it would really help if I replaced some of the "guts" of the tank. A new bathroom is in the plans, but we have a new baby on the way, so I don't want to tear into it at this point. At worse case I will install a new toilet to fix the problem.
Thanks for your help