A lot of the carb gurus now recommend replacing the jets every year or two with the current pump fuels. The pilot jets being the most problematic with it's small openings. It only takes one tiny deposit to effect its performance and the costs are minimal to replace.

Also on smokers don't overlook the silencer/spark arrestor...one friend who shall remain nameless went through several hundred dollars of engine work only to find out it was a restricted screen type spark arrestor! Doh!

Cheers