Yes it has a "butterfly".
I tried to take it off when assemblimg the motor and the result was a stalling engine, had to mount it back and then all worked fine. Did not get a intake with the engine so I used the old one.
The pump has one lever for shutoff which is connected to the "dragstart" and one lever that is connected to all rods in the engine
The "gas-lever" goes to max 75% of its possible travel when pedal is to the floor, at the same time the "butterfly is wide open.

Remember that i checked the diaphragm and it was ok, but it was hard to understand the construction!