Hello! So, I read this passage and this type of English is very context dependent because those the phrases are NOT used in every day speak. I've only ever heard of "run a blazer" which essentially means "to trick, to deceive". Blazer in this context is "lie" and not the piece of clothing. The only time I've ever heard "run a blazer" was back in my 9th grade Literature class... haha.
For "I hung up my gentle honk", I really have no idea but I can take a stab at it. Don't take this as correct, but if I were to describe those 2 paragraphs in modern day speak it it would be:
"Are you sure you're not tricking yourself?"
"Well, if I was, here is all of the evidence and you can tell me if I am tricking myself."
(I'm basing this off of, "... gave him free license to call it.")
If anyone else has any idea or comment, I'd love to hear it.