One other thing
I believe the C85 in our Luscombe has no accelerator pump in the carburettor and the 65 is probably similar.
The function of the pump is to squirt an extra dose of fuel into the venturi when the throttle is advanced and temporarily richen the mixture.
This is because opening the throttle allows more air through the venturi, momentarily weakening the mixture until the fuel overcomes its natural inertia and starts flowing at a higher rate. Opening the throttle a tad too quickly without an accelerator pump can cause a momentary reduction in power.