Fuel percolation. This subject has been mentioned before, but the correct name for the problem doesn't show up in a forum search, so I thought it would be nice to start a new thread with it.
This problem has given me a fit this summer, and I am going to be working on some ideas to solve it, such as
Thicker base gasket
Plastic washers under anchor stud nuts
After-run fan auto or manual
Wrap on downpipe
Using an infrared thermometer, I found that on a hot day of running, the temp of the carb base climbed from 138F to 170F after 5 min. of shut-down.
The intake manifold has a coolant passage for keeping fuel atomized on a cold start, but I have wondered if it helps or hurts the carb temp after the engine is shut off.
So I am wondering if the heat into the carb is coming from the hot coolant in the intake manifold, or from the heat of the exhaust manifold coming up through the intake manifold?