I’ve got a problem. We’re suppose to stripe a food manufacturing plant’s interior safety lines. We got the go ahead and we’re told that our 3900s would work just fine. We get there all set to paint, and out comes yet another head figure…this one apparently is the only one in the know and explains that a gas engine will not be used in a plant. It’s never really been an issue at other food production facilities…but here we are. I’ve seen some fabricated compressed air units…but I saw this s90 and thought that maybe I’d be able to use it. Despite it being for field striping I was told that it would push undiluted latex through…and that the single component interior striping paint would work as well. I managed to get my hands on a unit to demo, but I have had no luck getting any assemblance of a usable line. To the point that I can prime and spray H20 through it with no problems….I introduce paint, and it refuse to transfer to the gun portion. Prime…paint sprays from prime tube…switch prime switch to paint…motor starts to sound like its struggling as if it’s trying to spray the paint through the gun, but back flows out the prime tube. There’s a hex tip with a ball valve (?) behind it…that if removed I can get paint flow…reinstalled hex and it and we’re back to square one. HELP? Solutions? Or do i need to price out traffic tape? Thanks!