Mechanical fuel pump question

After getting the YJ back together I stuck the output of the fuel pump into a bottle to see how much the fuel pump was pumping. Never paid much attention before BUT do mechanical fuel pumps 'surge' or is the lever only being hit slowly at startup. I just noticed that the fuel 'spurts' out and it runs, just curious.

mechanical fuel pumps that run off the camshaft typically deliver fuel in spurts--REAL STRONG spurts. (I remember one on a six cylinder Ford that would push a column of gas into the air about six feet when it was cranking.)

Correct. It is, after all, a diaphragm pump. Down stroke suck fuel into pump chamber, up stroke pumps it out to the carb. Doesn't matter to the engine because the fuel doesn't go directly in, it fills the carb float bowl and just sits there until the carb venturi sucks some out and the float drops enough to let more in. Mechanical pressure is only about 7 psi -- and more than that and the carb float wouldn't be able to shut it off when the bowl is full.