I made a toliet paper filter out of 6" plactic sewer pipe. I decored three rolls of tp slid them down over a 1" plastic pipe that I had drilled random holes in and capped. Then i set this assemble down inside the 6" and capped the bottom. Then I cut a 1" hole in my top 6" cap and slid it down over the 1" pipe. I drilled a small hole near bottom of the 6" pipe and installed a decored tire valve w/cap and thats my filtered oil drain. 

I am using a 3.5 minipetter as generator to charge mt battery bank. I was running waste motor oil for a while but it burned too smokey so now I use used hydraulic oil I get for free in it. Its runs much cleaner. Have not had any problems out of it YET!, but from reading these posts you guys are scaring the hell out of me concerning a runaway petter! I guess the rag stuff in air cleaner is the only way I could shut mine down quickly. I need to install a fuel shutoff. You are right concerning the fuel lines , they suck.

I ran waste motor oil in my 3.5 petter for a while. I filtered it through a toliet paper filter first. I now use used hydraulic oil I get for free. It burns much cleaner since it dont have carbon deposits in it. When I changed my filter element after running the motor oil through it there were bad sludge deposits in the filter. The hyd. oil leaves no sludge.