I have a genset that I bought used in 1994 and between then and about 2001 I ran it 3 or 4 times but it hasn't been started since. What we've done is drain the lube oil, replace all 3 oil filters, replace the OEM fuel filter, drain the diesel fuel as best that we could and are in the process of replacing all the fuel hoses as @ 50+ years they were pretty rotten. When we drained the fuel tank the color was pretty dark brown and twice it stopped from crud but we poked a screw driver in the drain and got it flowing. The fuel tank is located low in the frame and removing it doesn't seem feasible, so we wondered what could be done. My thought was installing an after market 3 micron filter after the lift or transfer pump but ahead of everything else in the fuel system. I would add that the lube oil looked good and the last time it ran it was fine. Any thoughts and help is appreciated.