[1] Gascolators are susceptible to the effects of heat from the co-located engine and exhaust components, which can cause fuel vapourization in the gascolator and vapour lock problems.
This usually manifests itself as a partial power loss in cruise flight.
[1] Some types of gascolators are equipped with a remote spring-loaded knob to drain them.
[1] Writer Tony Bingelis says of this type: A gascolator with a lazy man's quick drain (that is, one you can work standing up by merely pulling on a spring-loaded handle) has its shortcomings.
It is generally a heavier unit than a simple gascolator and is also more expensive.