drainage valve won't completely close
I can't find a point where tightening or loosening the drainage valve under the tank completely seals it, so when I run teh compressor it won't build beyond 90 PSI and runs constantly.
There is always air coming out of the bottom.
When I tighten it it opens the valave completely, but when I loosen it the problem never completely goes away (and eventually the screw comes out completely, opening the valve to full). Any suggestions as to how to fix the problem?
Hi Andrew.... I would surmise from your comments that your tank drain is scuppered.
Pull the plug, turn the tank drain all the way out, take the drain to your hardware or plumbing store, and get another valve that has the same thread as the one you pulled out.
Now is the chance to, if you want, put an elbow into the tank drain port, add a few inches of copper or plastic air line, and put the shut off valve out to the side of the air compressor where you can more conveniently reach it.
See the FITTINGS and NPT pages for more detail.