As a multiple boat owner I can tell you that you don't want a primer bulb under the hood on an automobile...First off I don't think the fire hazzard condition outweighs the benefits...Secondly, the bulbs get hard,brittle and get hairline cracks which usually with them being far away from a marine engine isn't as crucial...There's absolutely no heat where these are mounted in a marine environment.... Those bulbs are for 2 cycle,contained engines{outboards} not an inboard,mounted fuel tank v8..These are suction/gravity systems with no pressure the bulb isn't designed for any pressure application....
It's easy enough to add fuel to the carb using the methods already outlined...Although the bulb looks to be an easy way out it's just too risky and seriously misapplied in an automobile...And I guarantee you it won't pass inspection with it anywhere on the car..