Gas Tank Lesson

[Mitch//pa]

Mike, i am talking about the flap also, as it is not a vapor control device. it's to prevent installing and fueling with the wrong size nozzle and improper fuel for what its worth. the flap is supposed to prevent refueling until its pushed open by the appropriate size nozzle. its actually a bunch of crap IMO as there are to many ways around it like using a gas can, but its for the average joe lol. there are also slits or little holes around the circumference of the flap. your lower picture is the newer style cap less fill neck which does prevent vapors as there is no gas cap on that design. the gas cap is the vapor control in combination evaporative system..

[TDO]

When you talk about the spark arrester in the tank , I assume your talking about the screen in the filler hole. Mine is an aftermarket and just drops in. Filling with it in takes for ever. So I remove it while I fill it up, I keep it in because I believe it works like a baffle and keeps the gas from sloshing around the neck. No matter what it is I wouldn't hold a match over it. Vapor is what goes bang. Not the liquid.

[Purdy Swoft]

Most model A's that i've seen have had the spark arrester removed. The repro drop in type dangles around and interferes with the gas gauge float. Most probably have better sense that to hold a lit match over gas fumes. I think that about the only market for the spark arrester is for people that want them for judging purposes.