Porter cable fc350b only shoots in bump setting. Will not shoot in single fire setting.

SOURCE: porter cable roofing gun

The problem that you describe could be caused by three things. First remove the cylinder and look for a black rubber band around the cylinder about med section. There is an indention with holes where it is supposed to be. The band should fit snuggly so that it does not slip off during use. Secondly, check that the piston oring/plastic ring holds the piston in the cylinder without just dropping under its own weight. Third, the upper bumper could have a crack or missing piece. Remove it and check. (vinyl part in headvalve) Parts are available at dewalt repair center or www.toolpartsdirect.com. enjoy

SOURCE: porter cable fc350a frame nailer shoots just air

Could be a couple things, first are you using the right nails in the gun e.g. collation and degree. Second do the nails move freely in the magazine and how is the pusher spring on the nail does it have enough pressure. Then I would unplug from air remove all the nails andjust tap the nose on a piece of wood and does the driver drop? If so the piston Oring is worn and needs replaced, but if you do that I would recommend replacing all the rubber. Let me know and I would need the exact model number to come up with parts.

SOURCE: Why does my porter cable nail gun FN250B shoot

check the magazine bolts are tight and that the magazine is snug aginst the nose. also be sure you are using 16 gage brads and not 18 gage

SOURCE: I have a Porter Cable

You have some blown o-rings inside the head that won't keep air where it's needed to return the driver back to the top. Porter Cable used to make a driver maintenance kit (PN60011) but it's no longer available through them. You may be able to find it on a site like eBay. If not you'll have to order each o-ring seperately from a Porter Cable/Dewalt service center.

SOURCE: I have an older FR

Over time vinyl seals and orings become worn and do not hold pressure. You can revive the gun by removing the head and pulling out the headvalve. Remove the orings and clean, reinstall same orings and lubricate with silicone paste lube. If the surfaces where the orings contact are scratched, smooth with very fine sandpaper. Make sure that the cylinder seal seal fits snugly. Some cylinder seals are incorporated in the headvalve (ring of vinyl) and others snap over the cylinder. If this ring fits loose, air will leak past. If possible remove the ring and clean then apply RTV sealant and reinstall. There are orings in the trigger valve that are troublesome. It would be easier to replace the whole valve is air seems to be leaking from under the trigger. Oring kits are available on ebay and toolpartsdirect.com. Good luck