When I first joined OSS IRC chats I did the same - tried to be polite and only ask if people were up for answering.
But the reality is that you're wasting even more time with that formalism. Just get the question out there. If someone's free to answer you, they'll answer you.
But more than that, don't ask questions that a little googling will answer for you. That will get you ignored.
Similarly for obvious "please do my homework for me" questions.