I'm now finding eleven though I try and follow a service schedule but I'm finding that burning this dirty crap my service ain't good enough. Was having injector problems, didn't seem to be getting fuel very hard to start. After messing wit timing still hard to start. So I started taking the old injector pump apart. This pump I took off a few yrs ago and just now am I looking at it. It is filthy, this is one part that should be serviced at least once year. I just discovered you can pull apart injector tips and clean. This should be done about every oil change. Also I just discovered you can take the top con rod Bering out through the side cover ,it's a pain but can be done. I think after I turned a Bering I'll keep a close eye on that, maybe every 2 to 3 oil change. I'm going to have to make a check list just to keep track of this stuff. I have 12000 hr on it now still running good. I'm getting natural gas this year so I'm going to run it on duel fuel, wvo and ng. I just bought cheep a arrow k6 engine. I'm thinking I'd like to turn back into diesel if I can find parts that fit, well see.