I have a 15Yr. old Ariens self propelled walk behind mower that I only use 3 or 4 times a year to mow the weeds on a slope at the edge of the yard...to steep for the riding mower. This Ariens has a 6.5 B&S Intek engine, and when cold it starts and runs great. However, if I stop it for anything after a half hour...add gas, etc., it is Very Hard to restart. If I pull the air filter, it sound like the fuel is "boiling" in the carburetor. I have rebuilt the carb, and there is a fiber "spacer" between the carb and the cylinder, which I assume is supposed to act as a "heat sink", but nothing I've tried, so far, seems to cure the "Hot restart" condition. Any Ideas???