Advice for trouble seeking an engine miss.

[Dulcesuenos]

Hello have a 1020 hour Westerbeke 12c-2 has a faint but noticeable rough miss under load and no load. smooths out a bit at higher rpm above 2400 guessing thats just harmonics. I have replaced. Primary and secondary filters. Fuel lines, there is no surging at all so doubt it is air. It was hard to start had an issue with an injector had a tiny bit of a seepage around the base tightened it no problem. Could this be an injector issue? Or pump timing / valve adj? I plan on checking and adj valves this weekend. I can check pump timing but need to get shims to adj the pump height. I do have a 4 spare injectors and a spare inj pump. Just looking for someone who may have had similar issues. I have had so many issues with marine mechanics who suck i have lost most faith in them and do everything i can myself. I know i should get the injectors i have as spares pop tested to weed out any bad ones, thanks fir any advice!!!

[River Cruiser]

While running at the rpm where the miss is most notable crack the injector line nut on each injector. When you crack one that makes no change or the least amount of change start with that cylinder, may be a injector not properly atomizing the fuel. Good luck