Yanmar 2qm15 fuel problem
I have a 2qm15 which had gotten water in the tank several times before I figured out what was going on. I cleaned the tank, lines, replaced filters and it ran fine for awhile. Now it is difficult to start when cold, dumps raw fuel out the exhaust with black and white smoke, then mostly clears up, and will power up in or out of gear to almost full power. However, when I throttle back, then up again, it belches raw fuel, black and white smoke. I pulled the exhaust elbow and found the smaller line coming from the cylinder head into the elbow almost blocked. Cleaned it out and replaced the elbow, but still has raw fuel, black and white smoke out of the exhaust.
Received several suggestions from this forum that it might be injectors. I pulled them, sent to shop but the nozzles were fine. Noticed one nut on each retaining bracket was finger tight. I think they should be torqued to 12 lb. Could this be the problem, or any other suggestions? Shop guy didn't think it was the injector pump.