As many as it needs to coat the internal parts, I keep mine in a spray bottle so that when I squirt it in (with the backplate off) it spreads more evenly or if the engines still in the car then it's 4 rounds of 5 drops down the carb, plug out and spin the engine till my finger gets wet then refit the plug. Leave the engine at BDC, freshly oiled air filter on and blank up the exhaust. No chance of moisture damage then.