We have more than15 twin engined SAR/towing vessels
running several permutations of the 350*- 450 HP Yanmar 6LY engines. (6LY / 6LY3 / 6LY3A) powering Hamilton HJ274 water jets
. Yearly run ranges from a couple of hundred hours to around one thousand.
Main problem over the years has been related to sooting because of running at too low load. These engines must be run hard all the time (cruise at 3100 RPM). After testing, Yanmar has advised us to completely avoid running at 1800*- 2200 RPM as the turbo has not really kicked in yet and the injectors are squiring even more fuel as the RPM's increase.
We perform Yanmar specified Commercial Duty Service every 250 hours.
At around 5000 hours engines are ripped out and completely rebuilt. As mentioned above, sooting has been discovered as the main source for wear and tear or premature breakdowns.
A friend of mine has one of the 315 HP's. His turbo went bust last summer. Was there a series of turbo breakdowns on these engines?*I believe there was a class action suit against Yanmar some time back. Can't remember if it was related to turbo problems.
-- Edited by r-rossow on Thursday 25th of August 2011 03:39:04 AM