Odd Problem

If I read right you mentioned a gurgling sound. Hand touch the gas line close to the carb . If the line is hot your gas is vaporizing and not completly filling the chambers Check where your lines are run and how hot is the engine. You should not hear that sound unless there is not enough fuel in the carb and engine is hot. This is a strange situation but had happened to me and was my fuel line was hot (too close to engine and engine running on the hotter side) causing fuel to vaposize before it got to carb (not ness vapor lock but close). maybe that will help