To get my 70 HP Johnson 1987 on target with the boat I recently bought, I have been using auxillary Evinrude 6 gallon gas cans 50:1 mix instead of the old gas in the boat's gas tank! I noticed the 6 gallon containers have no vent in the cap. Is that normal? I am use to venting all of my smaller horsepower outboards with the gas container's vent cap. The 6 gallon containers have no vent cap! It runs great this way, but was just wondering how this can be?...........L