Briggs and Stratton Brute 19" push mower

[BiII]

This is probably the 550seriec ECO engine.

I would suggest you check the simplest things first. It could be as simple as a faulty or incorrect spark plug or a vapor lock in the fuel tank. The ECO engines have a reduced evaporative fuel tank cap so check it is still venting.

If it isn't as simple at than then dig a little deeper.

I did not mention that I have replaced the spark plug and cleaned the air filter