Photos of you and your Cob would help.
Does he take up a lot of leg?
To me.. 14.2 hands is a super tall horse.
I rode 12.3, 13.2 and 13.3 hand tall horses/ponies..none had any problems with my height or weight. I am very careful to listen to them..all are very opinionated and would let me know if they did not like something.
As for weight carrying ability.. depends on the bone and muscle mass of the horse. Tall horses or ponies do not mean they will be able to carry more weight.
My Stout boned wide Icelandic's and Fjords can carry more weight..than my friends 16 hand wide Arab,,another TB and so on.
The Friend with the 16 hand Arab..was... I would say 200lbs.. her Arab was always having back problems. My Fjord who was 13.3 wide and well built never was sore or had any problems with her weight. Granted at most it was a three hour ride in the hills.
So.. it just depends on the build of your cob.. if you listen to them..they will tell you if it is too much.