[Buzz]

Thanks for the reply, Wilf. I don't know why the timing would be any different than it was before. Nothing to do with timing was altered; but still worth a check. Sticky valve is a possibility however - how should I go about checking?
One thing that hit me as I was browsing Jegs for new carbs is that mine seems to have an electric choke - round black plastic cover on right side with 2 contacts. One is grounded, nothing connected to the other. Could this be part of the problem? What should be connected to the other contact?